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In recent discussions on ksummit-discuss[1], it was suggested to do a
sequence of probe, remove, probe for testing driver remove paths. This
adds a kconfig option for said test.
[1] https://lists.linuxfoundation.org/pipermail/ksummit-discuss/2016-August/003459.html
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Allow implementations of the match() callback in struct bus_type to
return errors and if it's -EPROBE_DEFER then queue the device for
deferred probing.
This is useful to buses such as AMBA in which devices are registered
before their matching information can be retrieved from the HW
(typically because a clock driver hasn't probed yet).
[changed if-else code structure, adjusted documentation to match the code,
extended comments]
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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If device_is_bound() is called on a device that's not been registered
yet, it will attepmt to dereference dev->p which is NULL, so avoid
that by checking dev->p in there against NULL.
Fixes: 6b9cb42752da "device core: add device_is_bound()"
Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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If a suitable prepare callback cannot be found for a given device and
its driver has no PM callbacks at all, assume that it can go direct to
complete when the system goes to sleep.
The reason for this is that there's lots of devices in a system that do
no PM at all and there's no reason for them to prevent their ancestors
to do direct_complete if they can support it.
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Adds a function that tells whether a device is already bound to a
driver.
This is needed to warn when there is an attempt to change the PM domain
of a device that has finished probing already. The reason why we want to
enforce that is because in the general case that can cause problems and
also that we can simplify code quite a bit if we can always assume that.
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The users of BUS_NOTIFY_BIND_DRIVER have no chance to do any cleanup in case of
a probe failure. In the result there might be problems, such as some resources
that had been allocated will continue to be allocated and therefore lead to a
resource leak.
Introduce a new notification to inform the subscriber that ->probe() failed. Do
the same in case of failed device_bind_driver() call.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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There are two common expectations among several subsystems/drivers that
deploys runtime PM support, but which isn't met by the driver core.
Expectation 1)
At ->probe() the subsystem/driver expects the runtime PM status of the
device to be RPM_SUSPENDED, which is the initial status being assigned at
device registration.
This expectation is especially common among some of those subsystems/
drivers that manages devices with an attached PM domain, as those requires
the ->runtime_resume() callback at the PM domain level to be invoked
during ->probe().
Moreover these subsystems/drivers entirely relies on runtime PM resources
being managed at the PM domain level, thus don't implement their own set
of runtime PM callbacks.
These are two scenarios that suffers from this unmet expectation.
i) A failed ->probe() sequence requests probe deferral:
->probe()
...
pm_runtime_enable()
pm_runtime_get_sync()
...
err:
pm_runtime_put()
pm_runtime_disable()
...
As there are no guarantees that such sequence turns the runtime PM status
of the device into RPM_SUSPENDED, the re-trying ->probe() may start with
the status in RPM_ACTIVE.
In such case the runtime PM core won't invoke the ->runtime_resume()
callback because of a pm_runtime_get_sync(), as it considers the device to
be already runtime resumed.
ii) A driver re-bind sequence:
At driver unbind, the subsystem/driver's >remove() callback invokes a
sequence of runtime PM APIs, to undo actions during ->probe() and to put
the device into low power state.
->remove()
...
pm_runtime_put()
pm_runtime_disable()
...
Similar as in the failing ->probe() case, this sequence don't guarantee
the runtime PM status of the device to turn into RPM_SUSPENDED.
Trying to re-bind the driver thus causes the same issue as when re-trying
->probe(), in the probe deferral scenario.
Expectation 2)
Drivers that invokes the pm_runtime_irq_safe() API during ->probe(),
triggers the runtime PM core to increase the usage count for the device's
parent and permanently make it runtime resumed.
The usage count is only dropped at device removal, which also allows it to
be runtime suspended again.
A re-trying ->probe() repeats the call to pm_runtime_irq_safe() and thus
once more triggers the usage count of the device's parent to be increased.
This leads to not only an imbalance issue of the usage count of the
device's parent, but also to keep it runtime resumed permanently even if
->probe() fails.
To address these issues, let's change the policy of the driver core to
meet these expectations. More precisely, at ->probe() failures and driver
unbind, restore the initial states of runtime PM.
Although to still allow subsystem's to control PM for devices that doesn't
->probe() successfully, don't restore the initial states unless runtime PM
is disabled.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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It is unsafe [1] if probing of devices will happen during suspend or
hibernation and system behavior will be unpredictable in this case.
So, let's prohibit device's probing in dpm_prepare() and defer their
probing instead. The normal behavior will be restored in
dpm_complete().
This patch introduces new DD core APIs:
device_block_probing()
It will disable probing of devices and defer their probes instead.
device_unblock_probing()
It will restore normal behavior and trigger re-probing of deferred
devices.
[1] https://lkml.org/lkml/2015/9/11/554
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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For pinctrl the "default" state is applied to pins before the driver's
probe function is called. This is normally a sensible thing to do,
but in some cases can cause problems. That's because the pins will
change state before the driver is given a chance to program how those
pins should behave.
As an example you might have a regulator that is controlled by a PWM
(output high = high voltage, output low = low voltage). The firmware
might leave this pin as driven high. If we allow the driver core to
reconfigure this pin as a PWM pin before the PWM's probe function runs
then you might end up running at too low of a voltage while we probe.
Let's introudce a new "init" state. If this is defined we'll set
pinctrl to this state before probe and then "default" after probe
(unless the driver explicitly changed states already).
An alternative idea that was thought of was to use the pre-existing
"sleep" or "idle" states and add a boolean property that we should
start in that mode. This was not done because the "init" state is
needed for correctness and those other states are only present (and
only transitioned in to and out of) when (optional) power management
is enabled.
Changes in v3:
- Moved declarations to pinctrl/devinfo.h
- Fixed author/SoB
Changes in v2:
- Added comment to pinctrl_init_done() as per Linus W.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Caesar Wang <wxt@rock-chips.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management and ACPI updates from Rafael Wysocki:
"From the number of commits perspective, the biggest items are ACPICA
and cpufreq changes with the latter taking the lead (over 50 commits).
On the cpufreq front, there are many cleanups and minor fixes in the
core and governors, driver updates etc. We also have a new cpufreq
driver for Mediatek MT8173 chips.
ACPICA mostly updates its debug infrastructure and adds a number of
fixes and cleanups for a good measure.
The Operating Performance Points (OPP) framework is updated with new
DT bindings and support for them among other things.
We have a few updates of the generic power domains framework and a
reorganization of the ACPI device enumeration code and bus type
operations.
And a lot of fixes and cleanups all over.
Included is one branch from the MFD tree as it contains some
PM-related driver core and ACPI PM changes a few other commits are
based on.
Specifics:
- ACPICA update to upstream revision 20150818 including method
tracing extensions to allow more in-depth AML debugging in the
kernel and a number of assorted fixes and cleanups (Bob Moore, Lv
Zheng, Markus Elfring).
- ACPI sysfs code updates and a documentation update related to AML
method tracing (Lv Zheng).
- ACPI EC driver fix related to serialized evaluations of _Qxx
methods and ACPI tools updates allowing the EC userspace tool to be
built from the kernel source (Lv Zheng).
- ACPI processor driver updates preparing it for future introduction
of CPPC support and ACPI PCC mailbox driver updates (Ashwin
Chaugule).
- ACPI interrupts enumeration fix for a regression related to the
handling of IRQ attribute conflicts between MADT and the ACPI
namespace (Jiang Liu).
- Fixes related to ACPI device PM (Mika Westerberg, Srinidhi
Kasagar).
- ACPI device registration code reorganization to separate the
sysfs-related code and bus type operations from the rest (Rafael J
Wysocki).
- Assorted cleanups in the ACPI core (Jarkko Nikula, Mathias Krause,
Andy Shevchenko, Rafael J Wysocki, Nicolas Iooss).
- ACPI cpufreq driver and ia64 cpufreq driver fixes and cleanups (Pan
Xinhui, Rafael J Wysocki).
- cpufreq core cleanups on top of the previous changes allowing it to
preseve its sysfs directories over system suspend/resume (Viresh
Kumar, Rafael J Wysocki, Sebastian Andrzej Siewior).
- cpufreq fixes and cleanups related to governors (Viresh Kumar).
- cpufreq updates (core and the cpufreq-dt driver) related to the
turbo/boost mode support (Viresh Kumar, Bartlomiej Zolnierkiewicz).
- New DT bindings for Operating Performance Points (OPP), support for
them in the OPP framework and in the cpufreq-dt driver plus related
OPP framework fixes and cleanups (Viresh Kumar).
- cpufreq powernv driver updates (Shilpasri G Bhat).
- New cpufreq driver for Mediatek MT8173 (Pi-Cheng Chen).
- Assorted cpufreq driver (speedstep-lib, sfi, integrator) cleanups
and fixes (Abhilash Jindal, Andrzej Hajda, Cristian Ardelean).
- intel_pstate driver updates including Skylake-S support, support
for enabling HW P-states per CPU and an additional vendor bypass
list entry (Kristen Carlson Accardi, Chen Yu, Ethan Zhao).
- cpuidle core fixes related to the handling of coupled idle states
(Xunlei Pang).
- intel_idle driver updates including Skylake Client support and
support for freeze-mode-specific idle states (Len Brown).
- Driver core updates related to power management (Andy Shevchenko,
Rafael J Wysocki).
- Generic power domains framework fixes and cleanups (Jon Hunter,
Geert Uytterhoeven, Rajendra Nayak, Ulf Hansson).
- Device PM QoS framework update to allow the latency tolerance
setting to be exposed to user space via sysfs (Mika Westerberg).
- devfreq support for PPMUv2 in Exynos5433 and a fix for an incorrect
exynos-ppmu DT binding (Chanwoo Choi, Javier Martinez Canillas).
- System sleep support updates (Alan Stern, Len Brown, SungEun Kim).
- rockchip-io AVS support updates (Heiko Stuebner).
- PM core clocks support fixup (Colin Ian King).
- Power capping RAPL driver update including support for Skylake H/S
and Broadwell-H (Radivoje Jovanovic, Seiichi Ikarashi).
- Generic device properties framework fixes related to the handling
of static (driver-provided) property sets (Andy Shevchenko).
- turbostat and cpupower updates (Len Brown, Shilpasri G Bhat,
Shreyas B Prabhu)"
* tag 'pm+acpi-4.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (180 commits)
cpufreq: speedstep-lib: Use monotonic clock
cpufreq: powernv: Increase the verbosity of OCC console messages
cpufreq: sfi: use kmemdup rather than duplicating its implementation
cpufreq: drop !cpufreq_driver check from cpufreq_parse_governor()
cpufreq: rename cpufreq_real_policy as cpufreq_user_policy
cpufreq: remove redundant 'policy' field from user_policy
cpufreq: remove redundant 'governor' field from user_policy
cpufreq: update user_policy.* on success
cpufreq: use memcpy() to copy policy
cpufreq: remove redundant CPUFREQ_INCOMPATIBLE notifier event
cpufreq: mediatek: Add MT8173 cpufreq driver
dt-bindings: mediatek: Add MT8173 CPU DVFS clock bindings
PM / Domains: Fix typo in description of genpd_dev_pm_detach()
PM / Domains: Remove unusable governor dummies
PM / Domains: Make pm_genpd_init() available to modules
PM / domains: Align column headers and data in pm_genpd_summary output
powercap / RAPL: disable the 2nd power limit properly
tools: cpupower: Fix error when running cpupower monitor
PM / OPP: Drop unlikely before IS_ERR(_OR_NULL)
PM / OPP: Fix static checker warning (broken 64bit big endian systems)
...
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Now device's shutdown sequence is performed in reverse order of their
registration in devices_kset list and this sequence corresponds to the
reverse device's creation order. So, devices_kset data tracks
"parent<-child" device's dependencies only.
Unfortunately, that's not enough and causes problems in case of
implementing board's specific shutdown procedures. For example [1]:
"DRA7XX_evm uses PCF8575 and one of the PCF output lines feeds to
MMC/SD and this line should be driven high in order for the MMC/SD to
be detected. This line is modelled as regulator and the hsmmc driver
takes care of enabling and disabling it. In the case of 'reboot',
during shutdown path as part of it's cleanup process the hsmmc driver
disables this regulator. This makes MMC boot not functional."
To handle this issue the .shutdown() callback could be implemented
for PCF8575 device where corresponding GPIO pins will be configured to
states, required for correct warm/cold reset. This can be achieved
only when all .shutdown() callbacks have been called already for all
PCF8575's consumers. But devices_kset is not filled correctly now:
devices_kset: Device61 4e000000.dmm
devices_kset: Device62 48070000.i2c
devices_kset: Device63 48072000.i2c
devices_kset: Device64 48060000.i2c
devices_kset: Device65 4809c000.mmc
...
devices_kset: Device102 fixedregulator-sd
...
devices_kset: Device181 0-0020 // PCF8575
devices_kset: Device182 gpiochip496
devices_kset: Device183 0-0021 // PCF8575
devices_kset: Device184 gpiochip480
As can be seen from above .shutdown() callback for PCF8575 will be called
before its consumers, which, in turn means, that any changes of PCF8575
GPIO's pins will be or unsafe or overwritten later by GPIO's consumers.
The problem can be solved if devices_kset list will be filled not only
according device creation order, but also according device's probing
order to track "supplier<-consumer" dependencies also.
Hence, as a fix, lets add devices_kset_move_last(),
devices_kset_move_before(), devices_kset_move_after() and call them
from device_move() and also add call of devices_kset_move_last() in
really_probe(). After this change all entries in devices_kset will
be sorted according to device's creation ("parent<-child") and
probing ("supplier<-consumer") order.
devices_kset after:
devices_kset: Device121 48070000.i2c
devices_kset: Device122 i2c-0
...
devices_kset: Device147 regulator.24
devices_kset: Device148 0-0020
devices_kset: Device149 gpiochip496
devices_kset: Device150 0-0021
devices_kset: Device151 gpiochip480
devices_kset: Device152 0-0019
...
devices_kset: Device372 fixedregulator-sd
devices_kset: Device373 regulator.29
devices_kset: Device374 4809c000.mmc
devices_kset: Device375 mmc0
[1] http://www.spinics.net/lists/linux-mmc/msg29825.html
Cc: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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If the parent is still suspended when driver probe is
attempted, the result may be failure.
For example, if the parent is a PCI MFD device that has been
suspended when we try to probe our device, any register
reads will return 0xffffffff.
To fix the problem, making sure the parent is always awake
before attempting driver probe.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Signed-off-by: Shailendra Verma <shailendra.capricorn@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit f2411da74698 ("driver-core: add driver module asynchronous probe
support") broke build in case modules are disabled, because in this case
"struct module" is not defined and we can't dereference it. Let's define
module_requested_async_probing() helper and stub it out if modules are
disabled.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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It is only used within dd.c and thus need not be global.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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There are drivers that can not be probed asynchronously. One such group
is platform drivers registered with platform_driver_probe(), which
expects driver's probe routine be discarded after the driver has been
registered and initial binding attempt executed. Also
platform_driver_probe() an error when no devices were bound to the
driver, allowing failing to load such driver module altogether.
Other drivers do not work well with asynchronous probing because of
driver bug or not optimal driver organization.
To allow using such drivers even when user requests asynchronous probing
as default boot strategy, let's allow them to opt out.
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Some init systems may wish to express the desire to have device drivers
run their probe() code asynchronously. This implements support for this
and allows userspace to request async probe as a preference through a
generic shared device driver module parameter, async_probe.
Implementation for async probe is supported through a module parameter
given that since synchronous probe has been prevalent for years some
userspace might exist which relies on the fact that the device driver
will probe synchronously and the assumption that devices it provides
will be immediately available after this.
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Some devices take a long time when initializing, and not all drivers are
suited to initialize their devices when they are open. For example,
input drivers need to interrogate their devices in order to publish
device's capabilities before userspace will open them. When such drivers
are compiled into kernel they may stall entire kernel initialization.
This change allows drivers request for their probe functions to be
called asynchronously during driver and device registration (manual
binding is still synchronous). Because async_schedule is used to perform
asynchronous calls module loading will still wait for the probing to
complete.
Note that the end goal is to make the probing asynchronous by default,
so annotating drivers with PROBE_PREFER_ASYNCHRONOUS is a temporary
measure that allows us to speed up boot process while we validating and
fixing the rest of the drivers and preparing userspace.
This change is based on earlier patch by "Luis R. Rodriguez"
<mcgrof@suse.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management and ACPI updates from Rafael Wysocki:
"These are mostly fixes and cleanups all over, although there are a few
items that sort of fall into the new feature category.
First off, we have new callbacks for PM domains that should help us to
handle some issues related to device initialization in a better way.
There also is some consolidation in the unified device properties API
area allowing us to use that inferface for accessing data coming from
platform initialization code in addition to firmware-provided data.
We have some new device/CPU IDs in a few drivers, support for new
chips and a new cpufreq driver too.
Specifics:
- Generic PM domains support update including new PM domain callbacks
to handle device initialization better (Russell King, Rafael J
Wysocki, Kevin Hilman)
- Unified device properties API update including a new mechanism for
accessing data provided by platform initialization code (Rafael J
Wysocki, Adrian Hunter)
- ARM cpuidle update including ARM32/ARM64 handling consolidation
(Daniel Lezcano)
- intel_idle update including support for the Silvermont Core in the
Baytrail SOC and for the Airmont Core in the Cherrytrail and
Braswell SOCs (Len Brown, Mathias Krause)
- New cpufreq driver for Hisilicon ACPU (Leo Yan)
- intel_pstate update including support for the Knights Landing chip
(Dasaratharaman Chandramouli, Kristen Carlson Accardi)
- QorIQ cpufreq driver update (Tang Yuantian, Arnd Bergmann)
- powernv cpufreq driver update (Shilpasri G Bhat)
- devfreq update including Tegra support changes (Tomeu Vizoso,
MyungJoo Ham, Chanwoo Choi)
- powercap RAPL (Running-Average Power Limit) driver update including
support for Intel Broadwell server chips (Jacob Pan, Mathias Krause)
- ACPI device enumeration update related to the handling of the
special PRP0001 device ID allowing DT-style 'compatible' property
to be used for ACPI device identification (Rafael J Wysocki)
- ACPI EC driver update including limited _DEP support (Lan Tianyu,
Lv Zheng)
- ACPI backlight driver update including a new mechanism to allow
native backlight handling to be forced on non-Windows 8 systems and
a new quirk for Lenovo Ideapad Z570 (Aaron Lu, Hans de Goede)
- New Windows Vista compatibility quirk for Sony VGN-SR19XN (Chen Yu)
- Assorted ACPI fixes and cleanups (Aaron Lu, Martin Kepplinger,
Masanari Iida, Mika Westerberg, Nan Li, Rafael J Wysocki)
- Fixes related to suspend-to-idle for the iTCO watchdog driver and
the ACPI core system suspend/resume code (Rafael J Wysocki, Chen Yu)
- PM tracing support for the suspend phase of system suspend/resume
transitions (Zhonghui Fu)
- Configurable delay for the system suspend/resume testing facility
(Brian Norris)
- PNP subsystem cleanups (Peter Huewe, Rafael J Wysocki)"
* tag 'pm+acpi-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (74 commits)
ACPI / scan: Fix NULL pointer dereference in acpi_companion_match()
ACPI / scan: Rework modalias creation when "compatible" is present
intel_idle: mark cpu id array as __initconst
powercap / RAPL: mark rapl_ids array as __initconst
powercap / RAPL: add ID for Broadwell server
intel_pstate: Knights Landing support
intel_pstate: remove MSR test
cpufreq: fix qoriq uniprocessor build
ACPI / scan: Take the PRP0001 position in the list of IDs into account
ACPI / scan: Simplify acpi_match_device()
ACPI / scan: Generalize of_compatible matching
device property: Introduce firmware node type for platform data
device property: Make it possible to use secondary firmware nodes
PM / watchdog: iTCO: stop watchdog during system suspend
cpufreq: hisilicon: add acpu driver
ACPI / EC: Call acpi_walk_dep_device_list() after installing EC opregion handler
cpufreq: powernv: Report cpu frequency throttling
intel_idle: Add support for the Airmont Core in the Cherrytrail and Braswell SOCs
intel_idle: Update support for Silvermont Core in Baytrail SOC
PM / devfreq: tegra: Register governor on module init
...
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Currently probe deferral prints a message every time a device requests
deferral at info severity (which is displayed by default). This can have
an impact on system boot times with serial consoles and is generally quite
noisy.
Since subsystems and drivers should already be logging the specific reason
for probe deferral in order to aid users in understanding problems the
messages from the driver core should be redundant lower the severity of
the messages printed, cutting down on the volume of output on the console.
This does mean that if the drivers and subsystems aren't doing a good job
we get no output on the console by default. Ideally we'd be able to arrange
to print if nothing else printed, though that's a little fun. Even better
would be to come up with a mechanism that explicitly does dependencies so
we don't have to keep polling and erroring.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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There are series of comparisons of the 'ret' variable on the failure path of
really_probe(), so the *switch* statement seems more appropriate there.
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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If PM domains are in use, it may be necessary to prepare the code
handling a PM domain for driver probing. For example, in some
cases device drivers rely on the ability to power on the devices
with the help of the IO runtime PM framework and the PM domain
code needs to be ready for that. Also, if that code has not been
fully initialized yet, the driver probing should be deferred.
Moreover, after the probing is complete, it may be necessary to
put the PM domain in question into the state reflecting the current
needs of the devices in it, for example, so that power is not drawn
in vain. The same should be done after removing a driver from
a device, as the PM domain state may need to be changed to reflect
the new situation.
For these reasons, introduce new PM domain callbacks, ->activate,
->sync and ->dismiss called, respectively, before probing for a
device driver, after the probing has completed successfully and
if the probing has failed or the driver has been removed.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The deferred_probe_work_func() function is locally scoped, therefore an
associated kerneldoc comment isn't very useful. Replace the kerneldoc
opening marker (/**) with a regular block comment marker (/*) to avoid
the comment from being parsed by kerneldoc. This gets rid of a warning
caused by a missing description for the "work" argument.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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dev_set_drvdata and dev_get_drvdata are now simple enough again that
we can inline them as they used to be before commit b40284378.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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There is no point in calling dev_get_drvdata without a valid device.
So checking for dev == NULL is pointless. If such a check is ever
needed - which I doubt - the driver should do it before calling
dev_get_drvdata.
We were returning NULL if dev was NULL, which the caller certainly did
not expect anyway, so that was only delaying the crash if the caller
is not paying attention.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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dev_set_drvdata can no longer fail, so it could return void.
All callers have hopefully been updated to no longer check for the
return value.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Having to allocate memory as part of dev_set_drvdata() is a problem
because that memory may never get freed if the device itself is not
created. So move driver_data back to struct device.
This is a partial revert of commit b4028437.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When the kernel is built with CONFIG_PREEMPT it is possible to reach a state
when all modules loaded but some driver still stuck in the deferred list
and there is a need for external event to kick the deferred queue to probe
these drivers.
The issue has been observed on embedded systems with CONFIG_PREEMPT enabled,
audio support built as modules and using nfsroot for root filesystem.
The following log fragment shows such sequence when all audio modules
were loaded but the sound card is not present since the machine driver has
failed to probe due to missing dependency during it's probe.
The board is am335x-evmsk (McASP<->tlv320aic3106 codec) with davinci-evm
machine driver:
...
[ 12.615118] davinci-mcasp 4803c000.mcasp: davinci_mcasp_probe: ENTER
[ 12.719969] davinci_evm sound.3: davinci_evm_probe: ENTER
[ 12.725753] davinci_evm sound.3: davinci_evm_probe: snd_soc_register_card
[ 12.753846] davinci-mcasp 4803c000.mcasp: davinci_mcasp_probe: snd_soc_register_component
[ 12.922051] davinci-mcasp 4803c000.mcasp: davinci_mcasp_probe: snd_soc_register_component DONE
[ 12.950839] davinci_evm sound.3: ASoC: platform (null) not registered
[ 12.957898] davinci_evm sound.3: davinci_evm_probe: snd_soc_register_card DONE (-517)
[ 13.099026] davinci-mcasp 4803c000.mcasp: Kicking the deferred list
[ 13.177838] davinci-mcasp 4803c000.mcasp: really_probe: probe_count = 2
[ 13.194130] davinci_evm sound.3: snd_soc_register_card failed (-517)
[ 13.346755] davinci_mcasp_driver_init: LEAVE
[ 13.377446] platform sound.3: Driver davinci_evm requests probe deferral
[ 13.592527] platform sound.3: really_probe: probe_count = 0
In the log the machine driver enters it's probe at 12.719969 (this point it
has been removed from the deferred lists). McASP driver already executing
it's probing (since 12.615118).
The machine driver tries to construct the sound card (12.950839) but did
not found one of the components so it fails. After this McASP driver
registers all the ASoC components (the machine driver still in it's probe
function after it failed to construct the card) and the deferred work is
prepared at 13.099026 (note that this time the machine driver is not in the
lists so it is not going to be handled when the work is executing).
Lastly the machine driver exit from it's probe and the core places it to
the deferred list but there will be no other driver going to load and the
deferred queue is not going to be kicked again - till we have external event
like connecting USB stick, etc.
The proposed solution is to try the deferred queue once more when the last
driver is asking for deferring and we had drivers loaded while this last
driver was probing.
This way we can avoid drivers stuck in the deferred queue.
Signed-off-by: Grant Likely <grant.likely@linaro.org>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Stable <stable@vger.kernel.org> # v3.4+
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pr_debug() parameters are reverse order of format string
Signed-off-by: Frank Rowand <frank.rowand@sonymobile.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit fa180eb448fa (PM / Runtime: Idle devices asynchronously after
probe|release) modified __device_release_driver() to call
pm_runtime_put(dev) instead of pm_runtime_put_sync(dev) before
detaching the driver from the device. However, that was a mistake,
because pm_runtime_put(dev) causes rpm_idle() to be queued up and
the driver may be gone already when that function is executed.
That breaks the assumptions the drivers have the right to make
about the core's behavior on the basis of the existing documentation
and actually causes problems to happen, so revert that part of
commit fa180eb448fa and restore the previous behavior of
__device_release_driver().
Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Fixes: fa180eb448fa (PM / Runtime: Idle devices asynchronously after probe|release)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Kevin Hilman <khilman@linaro.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Cc: 3.10+ <stable@vger.kernel.org> # 3.10+
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Putting devices into idle|suspend in a synchronous manner means we are
waiting for each device to become idle|suspended before the probe|release
is fully done.
This patch switch to use the asynchronous runtime PM API:s instead and
thus improves the parallelism since we can move on and handle the next
device in queue in an earlier phase.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core patches from Greg Kroah-Hartman:
"Here is the big driver core merge for 3.9-rc1
There are two major series here, both of which touch lots of drivers
all over the kernel, and will cause you some merge conflicts:
- add a new function called devm_ioremap_resource() to properly be
able to check return values.
- remove CONFIG_EXPERIMENTAL
Other than those patches, there's not much here, some minor fixes and
updates"
Fix up trivial conflicts
* tag 'driver-core-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (221 commits)
base: memory: fix soft/hard_offline_page permissions
drivercore: Fix ordering between deferred_probe and exiting initcalls
backlight: fix class_find_device() arguments
TTY: mark tty_get_device call with the proper const values
driver-core: constify data for class_find_device()
firmware: Ignore abort check when no user-helper is used
firmware: Reduce ifdef CONFIG_FW_LOADER_USER_HELPER
firmware: Make user-mode helper optional
firmware: Refactoring for splitting user-mode helper code
Driver core: treat unregistered bus_types as having no devices
watchdog: Convert to devm_ioremap_resource()
thermal: Convert to devm_ioremap_resource()
spi: Convert to devm_ioremap_resource()
power: Convert to devm_ioremap_resource()
mtd: Convert to devm_ioremap_resource()
mmc: Convert to devm_ioremap_resource()
mfd: Convert to devm_ioremap_resource()
media: Convert to devm_ioremap_resource()
iommu: Convert to devm_ioremap_resource()
drm: Convert to devm_ioremap_resource()
...
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One of the side effects of deferred probe is that some drivers which
used to be probed before initcalls completed are now happening slightly
later. This causes two problems.
- If a console driver gets deferred, then it may not be ready when
userspace starts. For example, if a uart depends on pinctrl, then the
uart will get deferred and /dev/console will not be available
- __init sections will be discarded before built-in drivers are probed.
Strictly speaking, __init functions should not be called in a drivers
__probe path, but there are a lot of drivers (console stuff again)
that do anyway. In the past it was perfectly safe to do so because all
built-in drivers got probed before the end of initcalls.
This patch fixes the problem by forcing the first pass of the deferred
list to complete at late_initcall time. This is late enough to catch the
drivers that are known to have the above issues.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Haojian Zhuang <haojian.zhuang@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable <stable@vger.kernel.org> # 3.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This makes the device core auto-grab the pinctrl handle and set
the "default" (PINCTRL_STATE_DEFAULT) state for every device
that is present in the device model right before probe. This will
account for the lion's share of embedded silicon devcies.
A modification of the semantics for pinctrl_get() is also done:
previously if the pinctrl handle for a certain device was already
taken, the pinctrl core would return an error. Now, since the
core may have already default-grabbed the handle and set its
state to "default", if the handle was already taken, this will
be disregarded and the located, previously instanitated handle
will be returned to the caller.
This way all code in drivers explicitly requesting their pinctrl
handlers will still be functional, and drivers that want to
explicitly retrieve and switch their handles can still do that.
But if the desired functionality is just boilerplate of this
type in the probe() function:
struct pinctrl *p;
p = devm_pinctrl_get_select_default(&dev);
if (IS_ERR(p)) {
if (PTR_ERR(p) == -EPROBE_DEFER)
return -EPROBE_DEFER;
dev_warn(&dev, "no pinctrl handle\n");
}
The discussion began with the addition of such boilerplate
to the omap4 keypad driver:
http://marc.info/?l=linux-input&m=135091157719300&w=2
A previous approach using notifiers was discussed:
http://marc.info/?l=linux-kernel&m=135263661110528&w=2
This failed because it could not handle deferred probes.
This patch alone does not solve the entire dilemma faced:
whether code should be distributed into the drivers or
if it should be centralized to e.g. a PM domain. But it
solves the immediate issue of the addition of boilerplate
to a lot of drivers that just want to grab the default
state. As mentioned, they can later explicitly retrieve
the handle and set different states, and this could as
well be done by e.g. PM domains as it is only related
to a certain struct device * pointer.
ChangeLog v4->v5 (Stephen):
- Simplified the devicecore grab code.
- Deleted a piece of documentation recommending that pins
be mapped to a device rather than hogged.
ChangeLog v3->v4 (Linus):
- Drop overzealous NULL checks.
- Move kref initialization to pinctrl_create().
- Seeking Tested-by from Stephen Warren so we do not disturb
the Tegra platform.
- Seeking ACK on this from Greg (and others who like it) so I
can merge it through the pinctrl subsystem.
ChangeLog v2->v3 (Linus):
- Abstain from using IS_ERR_OR_NULL() in the driver core,
Russell recently sent a patch to remove it. Handle the
NULL case explicitly even though it's a bogus case.
- Make sure we handle probe deferral correctly in the device
core file. devm_kfree() the container on error so we don't
waste memory for devices without pinctrl handles.
- Introduce reference counting into the pinctrl core using
<linux/kref.h> so that we don't release pinctrl handles
that have been obtained for two or more places.
ChangeLog v1->v2 (Linus):
- Only store a pointer in the device struct, and only allocate
this if it's really used by the device.
Cc: Felipe Balbi <balbi@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Mitch Bradley <wmb@firmworks.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Rickard Andersson <rickard.andersson@stericsson.com>
Cc: Russell King <linux@arm.linux.org.uk>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
[swarren: fixed and simplified error-handling in pinctrl_bind_pins(), to
correctly handle deferred probe. Removed admonition from docs not to use
pinctrl hogs for devices]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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The pm_runtime_get_noresume() calls before really_probe() and
before executing __device_attach() for each driver on the
device's bus cause problems to happen if probing fails and if the
driver has enabled runtime PM for the device in its .probe()
callback. Namely, in that case, if the device has been resumed
by the driver after enabling its runtime PM and if it turns out that
.probe() should return an error, the driver is supposed to suspend
the device and disable its runtime PM before exiting .probe().
However, because the device's runtime PM usage counter was
incremented by the core before calling .probe(), the driver's attempt
to suspend the device will not succeed and the device will remain in
the full-power state after the failing .probe() has returned.
To fix this issue, remove the pm_runtime_get_noresume() calls from
driver_probe_device() and from device_attach() and replace the
corresponding pm_runtime_put_sync() calls with pm_runtime_idle()
to preserve the existing behavior (which is to check if the device
is idle and to suspend it eventually in that case after probing).
Reported-and-tested-by: Kevin Hilman <khilman@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When deferred probe was originally added the idea was that devices which
defer their probes would move themselves to the end of dpm_list in order
to try to keep the assumptions that we're making about the list being in
roughly the order things should be suspended correct. However this hasn't
been what's been happening and doing it requires a lot of duplicated code
to do the moves.
Instead take a simple, brute force solution and have the deferred probe
code push devices to the end of dpm_list before it retries the probe. This
does mean we lock the dpm_list a bit more often but it's very simple and
the code shouldn't be a fast path. We do the move with the deferred mutex
dropped since doing things with fewer locks held simultaneously seems like
a good idea.
This approach was most recently suggested by Grant Likely.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Grant Likely <grant.likely@secretlab.ca>,
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This picks up the big printk fixes, and resolves a merge issue with:
drivers/extcon/extcon_gpio.c
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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1) drvdata is for a driver to store a pointer to driver specific data
2) If no driver is bound, there is no driver specific data associated with
the device
3) Thus logically drvdata should be NULL if no driver is bound.
But many drivers don't clear drvdata on device_release, or set drvdata
early on in probe and leave it set on probe error. Both of which results
in a dangling pointer in drvdata.
This patch enforce for drvdata to be NULL after device_release or on probe
failure.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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If driver requests probe deferral,
it will be added to deferred_probe_pending_list
by driver_deferred_probe_add(), but, it used list_add().
Because of that, deferred probe will be run as reversed order.
This patch uses list_add_tail(), and solved this issue.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Came in in the deferred probe patch, quick, clean them up before a
kernel janitor finds them and sends me 4 individual patches to fix them
up...
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Nothing outside of the driver core needs to get to the deferred probe
pointer, so move it inside the private area of 'struct device' so no one
tries to mess around with it.
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Allow drivers to report at probe time that they cannot get all the resources
required by the device, and should be retried at a later time.
This should completely solve the problem of getting devices
initialized in the right order. Right now this is mostly handled by
mucking about with initcall ordering which is a complete hack, and
doesn't even remotely handle the case where device drivers are in
modules. This approach completely sidesteps the issues by allowing
driver registration to occur in any order, and any driver can request
to be retried after a few more other drivers get probed.
v4: - Integrate Manjunath's addition of a separate workqueue
- Change -EAGAIN to -EPROBE_DEFER for drivers to trigger deferral
- Update comment blocks to reflect how the code really works
v3: - Hold off workqueue scheduling until late_initcall so that the bulk
of driver probes are complete before we start retrying deferred devices.
- Tested with simple use cases. Still needs more testing though.
Using it to get rid of the gpio early_initcall madness, or to replace
the ASoC internal probe deferral code would be ideal.
v2: - added locking so it should no longer be utterly broken in that regard
- remove device from deferred list at device_del time.
- Still completely untested with any real use case, but has been
boot tested.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dilan Lee <dilee@nvidia.com>
Cc: Manjunath GKondaiah <manjunath.gkondaiah@linaro.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: David Daney <david.daney@cavium.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When DEBUG_DRIVER is activated, be verbose and explicitly state when a
device<->driver match was rejected by the probe-function of the driver.
Now all code-paths report what is currently happening which helps
debugging, because you don't have to remember that no printout means
the match is rejected (and then you still don't know if it was because
of ENODEV or ENXIO).
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
|
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6
* 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (44 commits)
debugfs: Silence DEBUG_STRICT_USER_COPY_CHECKS=y warning
sysfs: remove "last sysfs file:" line from the oops messages
drivers/base/memory.c: fix warning due to "memory hotplug: Speed up add/remove when blocks are larger than PAGES_PER_SECTION"
memory hotplug: Speed up add/remove when blocks are larger than PAGES_PER_SECTION
SYSFS: Fix erroneous comments for sysfs_update_group().
driver core: remove the driver-model structures from the documentation
driver core: Add the device driver-model structures to kerneldoc
Translated Documentation/email-clients.txt
RAW driver: Remove call to kobject_put().
reboot: disable usermodehelper to prevent fs access
efivars: prevent oops on unload when efi is not enabled
Allow setting of number of raw devices as a module parameter
Introduce CONFIG_GOOGLE_FIRMWARE
driver: Google Memory Console
driver: Google EFI SMI
x86: Better comments for get_bios_ebda()
x86: get_bios_ebda_length()
misc: fix ti-st build issues
params.c: Use new strtobool function to process boolean inputs
debugfs: move to new strtobool
...
Fix up trivial conflicts in fs/debugfs/file.c due to the same patch
being applied twice, and an unrelated cleanup nearby.
|
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The driver core tries to prevent race conditions between runtime PM
and driver removal from happening by incrementing the runtime PM
usage counter of the device and executing pm_runtime_barrier() before
running the bus notifier and the ->remove() callbacks provided by the
device's subsystem or driver. This guarantees that, if a future
runtime suspend of the device has been scheduled or a runtime resume
or idle request has been queued up right before the driver removal,
it will be canceled or waited for to complete and no other
asynchronous runtime suspend or idle requests for the device will be
put into the PM workqueue until the ->remove() callback returns.
However, it doesn't prevent resume requests from being queued up
after pm_runtime_barrier() has been called and it doesn't prevent
pm_runtime_resume() from executing the device subsystem's runtime
resume callback. Morever, it prevents the device's subsystem or
driver from putting the device into the suspended state by calling
pm_runtime_suspend() from its ->remove() routine. This turns out to
be a major inconvenience for some subsystems and drivers that want to
leave the devices they handle in the suspended state.
To really prevent runtime PM callbacks from racing with the bus
notifier callback in __device_release_driver(), which is necessary,
because the notifier is used by some subsystems to carry out
operations affecting the runtime PM functionality, use
pm_runtime_get_sync() instead of the combination of
pm_runtime_get_noresume() and pm_runtime_barrier(). This will resume
the device if it's in the suspended state and will prevent it from
being suspended again until pm_runtime_put_*() is called.
To allow subsystems and drivers to put devices into the suspended
state by calling pm_runtime_suspend() from their ->remove() routines,
execute pm_runtime_put_sync() after running the bus notifier in
__device_release_driver(). This will require subsystems and drivers
to make their ->remove() callbacks avoid races with runtime PM
directly, but it will allow of more flexibility in the handling of
devices during the removal of their drivers.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
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Before commit
b402843 (Driver core: move dev_get/set_drvdata to drivers/base/dd.c)
calling dev_set_drvdata with dev=NULL was an unchecked error. After some
discussion about what to return in this case removing the check (and so
producing a null pointer exception) seems fine.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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When a device is registered to a bus it will be a) added to the list
of devices of the bus and b) bind to a driver (if one matches). As a
result of a driver being registered at this bus between a) and b) this
device could already be bound to a driver. This leads to a warning
and incorrect refcounting.
To fix this add a check to device_attach to identify an already bound
device.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Add BUS_NOTIFY_BIND_DRIVER as a bus notifier event.
For driver binding/unbinding we with this in
place have the following bus notifier events:
- BUS_NOTIFY_BIND_DRIVER - before ->probe()
- BUS_NOTIFY_BOUND_DRIVER - after ->probe()
- BUS_NOTIFY_UNBIND_DRIVER - before ->remove()
- BUS_NOTIFY_UNBOUND_DRIVER - after ->remove()
The event BUS_NOTIFY_BIND_DRIVER allows bus code
to be notified that ->probe() is about to be called.
Useful for bus code that needs to setup hardware before
the driver gets to run. With this in place platform
drivers can be loaded and unloaded as modules and the
new BIND event allows bus code to control for instance
device clocks that must be enabled before the driver
can be executed.
Without this patch there is no way for the bus code to
get notified that a modular driver is about to be probed.
Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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