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2017-03-31Merge branches 'pm-cpufreq-fixes' and 'pm-cpuidle-fixes'Rafael J. Wysocki
* pm-cpufreq-fixes: cpufreq: Fix creation of symbolic links to policy directories * pm-cpuidle-fixes: cpuidle: powernv: Pass correct drv->cpumask for registration
2017-03-27cpufreq: Fix creation of symbolic links to policy directoriesRafael J. Wysocki
The cpufreq core only tries to create symbolic links from CPU directories in sysfs to policy directories in cpufreq_add_dev(), either when a given CPU is registered or when the cpufreq driver is registered, whichever happens first. That is not sufficient, however, because cpufreq_add_dev() may be called for an offline CPU whose policy object has not been created yet and, quite obviously, the symbolic cannot be added in that case. Fix that by making cpufreq_online() attempt to add symbolic links to policy objects for the CPUs in the related_cpus mask of every new policy object created by it. The cpufreq_driver_lock locking around the for_each_cpu() loop in cpufreq_online() is dropped, because it is not necessary and the code is somewhat simpler without it. Moreover, failures to create a symbolic link will not be regarded as hard errors any more and the CPUs without those links will not be taken offline automatically, but that should not be problematic in practice. Reported-and-tested-by: Prashanth Prakash <pprakash@codeaurora.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: 4.9+ <stable@vger.kernel.org> # 4.9+
2017-03-24Merge branches 'pm-cpufreq-fixes', 'pm-cpufreq-sched-fixes' and ↵Rafael J. Wysocki
'intel_pstate-fixes' * pm-cpufreq-fixes: cpufreq: Restore policy min/max limits on CPU online * pm-cpufreq-sched-fixes: cpufreq: schedutil: Fix per-CPU structure initialization in sugov_start() * intel_pstate-fixes: cpufreq: intel_pstate: Fix policy data management in passive mode cpufreq: intel_pstate: One set of global limits in active mode
2017-03-22cpufreq: Restore policy min/max limits on CPU onlineViresh Kumar
On CPU online the cpufreq core restores the previous governor (or the previous "policy" setting for ->setpolicy drivers), but it does not restore the min/max limits at the same time, which is confusing, inconsistent and real pain for users who set the limits and then suspend/resume the system (using full suspend), in which case the limits are reset on all CPUs except for the boot one. Fix this by making cpufreq_online() restore the limits when an inactive policy is brought online. The commit log and patch are inspired from Rafael's earlier work. Reported-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: 4.3+ <stable@vger.kernel.org> # 4.3+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-03-21cpufreq: intel_pstate: Fix policy data management in passive modeRafael J. Wysocki
The policy->cpuinfo.max_freq and policy->max updates in intel_cpufreq_turbo_update() are excessive as they are done for no good reason and may lead to problems in principle, so they should be dropped. However, after dropping them intel_cpufreq_turbo_update() becomes almost entirely pointless, because the check made by it is made again down the road in intel_pstate_prepare_request(). The only thing in it that still needs to be done is the call to update_turbo_state(), so drop intel_cpufreq_turbo_update() altogether and make its callers invoke update_turbo_state() directly instead of it. In addition to that, fix intel_cpufreq_verify_policy() so that it checks global.no_turbo in addition to global.turbo_disabled when updating policy->cpuinfo.max_freq to make it consistent with intel_pstate_verify_policy(). Fixes: 001c76f05b01 (cpufreq: intel_pstate: Generic governors support) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-03-18cpufreq: intel_pstate: One set of global limits in active modeRafael J. Wysocki
In the active mode intel_pstate currently uses two sets of global limits, each associated with one of the possible scaling_governor settings in that mode: "powersave" or "performance". The driver switches over from one of those sets to the other depending on the scaling_governor setting for the last CPU whose per-policy cpufreq interface in sysfs was last used to change parameters exposed in there. That obviously leads to no end of issues when the scaling_governor settings differ between CPUs. The most recent issue was introduced by commit a240c4aa5d0f (cpufreq: intel_pstate: Do not reinit performance limits in ->setpolicy) that eliminated the reinitialization of "performance" limits in intel_pstate_set_policy() preventing the max limit from being set to anything below 100, among other things. Namely, an undesirable side effect of commit a240c4aa5d0f is that now, after setting scaling_governor to "performance" in the active mode, the per-policy limits for the CPU in question go to the highest level and stay there even when it is switched back to "powersave" later. As it turns out, some distributions set scaling_governor to "performance" temporarily for all CPUs to speed-up system initialization, so that change causes them to misbehave later. To fix that, get rid of the performance/powersave global limits split and use just one set of global limits for everything. From the user's persepctive, after this modification, when scaling_governor is switched from "performance" to "powersave" or the other way around on one CPU, the limits settings (ie. the global max/min_perf_pct and per-policy scaling_max/min_freq for any CPUs) will not change. Still, switching from "performance" to "powersave" or the other way around changes the way in which P-states are selected and in particular "performance" causes the driver to always request the highest P-state it is allowed to ask for for the given CPU. Fixes: a240c4aa5d0f (cpufreq: intel_pstate: Do not reinit performance limits in ->setpolicy) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-03-18Merge branches 'pm-cpufreq-fixes' and 'intel_pstate-fixes'Rafael J. Wysocki
* pm-cpufreq-fixes: cpufreq: Fix and clean up show_cpuinfo_cur_freq() * intel_pstate-fixes: cpufreq: intel_pstate: Avoid percentages in limits-related computations cpufreq: intel_pstate: Correct frequency setting in the HWP mode cpufreq: intel_pstate: Update pid_params.sample_rate_ns in pid_param_set()
2017-03-16cpufreq: Fix and clean up show_cpuinfo_cur_freq()Rafael J. Wysocki
There is a missing newline in show_cpuinfo_cur_freq(), so add it, but while at it clean that function up somewhat too. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: All applicable <stable@vger.kernel.org>
2017-03-15cpufreq: intel_pstate: Avoid percentages in limits-related computationsRafael J. Wysocki
Currently, intel_pstate_update_perf_limits() first converts the policy minimum and maximum limits into percentages of the maximum turbo frequency (rounding up to an integer) and then converts these percentages to fractions (by using fixed-point arithmetic to divide them by 100). That introduces a rounding error unnecessarily, because the fractions can be obtained by carrying out fixed-point divisions directly on the input numbers. Rework the computations in intel_pstate_hwp_set() to use fractions instead of percentages (and drop redundant local variables from there) and modify intel_pstate_update_perf_limits() to compute the fractions directly and percentages out of them. While at it, introduce percent_ext_fp() for converting percentages to fractions (with extended number of fraction bits) and use it in the computations. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-03-14cpufreq: intel_pstate: Correct frequency setting in the HWP modeSrinivas Pandruvada
In the functions intel_pstate_hwp_set(), min/max range from HWP capability MSR along with max_perf_pct and min_perf_pct, is used to set the HWP request MSR. In some cases this doesn't result in the correct HWP max/min in HWP request. For example: In the following case: HWP capabilities from MSR 0x771 0x70a1220 Here cpufreq min/max frequencies from above MSR dump are 700MHz and 3.2GHz respectively. This will result in hwp_min = 0x07 hwp_max = 0x20 To limit max frequency to 2GHz: perf_limits->max_perf_pct = 63 (2GHz as a percent of 3.2GHz rounded up) With the current calculation: adj_range = max_perf_pct * range / 100; adj_range = 63 * (32 - 7) / 100 adj_range = 15 max = hw_min + adj_range; max = 7 + 15 = 22 This will result in HWP request of 0x160f, which will result in a frequency cap of 2.2GHz not 2GHz. The problem with the above calculation is that hwp_min of 7 is treated as 0% in the range. But max_perf_pct is calculated with respect to minimum as 0 and max as 3.2GHz or hwp_max, so adding hwp_min to it will result in more than the desired. Since the min_perf_pct and max_perf_pct is already a percent of max frequency or hwp_max, this min/max HWP request value can be calculated directly applying these percentage to hwp_max. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-03-13cpufreq: intel_pstate: Update pid_params.sample_rate_ns in pid_param_set()Rafael J. Wysocki
Fix the debugfs interface for PID tuning to actually update pid_params.sample_rate_ns on PID parameters updates, as changing pid_params.sample_rate_ms via debugfs has no effect now. Fixes: a4675fbc4a7a (cpufreq: intel_pstate: Replace timers with utilization update callbacks) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2017-03-09Merge branch 'pm-cpufreq'Rafael J. Wysocki
* pm-cpufreq: cpufreq: intel_pstate: Do not reinit performance limits in ->setpolicy cpufreq: intel_pstate: Fix intel_pstate_verify_policy() cpufreq: intel_pstate: Fix global settings in active mode cpufreq: Add the "cpufreq.off=1" cmdline option cpufreq: intel_pstate: Avoid triggering cpu_frequency tracepoint unnecessarily cpufreq: intel_pstate: Fix intel_cpufreq_verify_policy() cpufreq: intel_pstate: Do not use performance_limits in passive mode
2017-03-06cpufreq: intel_pstate: Do not reinit performance limits in ->setpolicyRafael J. Wysocki
If the current P-state selection algorithm is set to "performance" in intel_pstate_set_policy(), the limits may be initialized from scratch, but only if no_turbo is not set and the maximum frequency allowed for the given CPU (i.e. the policy object representing it) is at least equal to the max frequency supported by the CPU. In all of the other cases, the limits will not be updated. For example, the following can happen: # cat intel_pstate/status active # echo performance > cpufreq/policy0/scaling_governor # cat intel_pstate/min_perf_pct 100 # echo 94 > intel_pstate/min_perf_pct # cat intel_pstate/min_perf_pct 100 # cat cpufreq/policy0/scaling_max_freq 3100000 echo 3000000 > cpufreq/policy0/scaling_max_freq # cat intel_pstate/min_perf_pct 94 # echo 95 > intel_pstate/min_perf_pct # cat intel_pstate/min_perf_pct 95 That is confusing for two reasons. First, the initial attempt to change min_perf_pct to 94 seems to have no effect, even though setting the global limits should always work. Second, after changing scaling_max_freq for policy0 the global min_perf_pct attribute shows 94, even though it should have not been affected by that operation in principle. Moreover, the final attempt to change min_perf_pct to 95 worked as expected, because scaling_max_freq for the only policy with scaling_governor equal to "performance" was different from the maximum at that time. To make all that confusion go away, modify intel_pstate_set_policy() so that it doesn't reinitialize the limits at all. At the same time, change intel_pstate_set_performance_limits() to set min_sysfs_pct to 100 in the "performance" limits set so that switching the P-state selection algorithm to "performance" causes intel_pstate/min_perf_pct in sysfs to go to 100 (or whatever value min_sysfs_pct in the "performance" limits is set to later). That requires per-CPU limits to be initialized explicitly rather than by copying the global limits to avoid setting min_sysfs_pct in the per-CPU limits to 100. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-03-06cpufreq: intel_pstate: Fix intel_pstate_verify_policy()Rafael J. Wysocki
The code added to intel_pstate_verify_policy() by commit 1443ebbacfd7 (cpufreq: intel_pstate: Fix sysfs limits enforcement for performance policy) should use perf_limits instead of limits, because otherwise setting global limits via sysfs may affect policies inconsistently. For example, in the sequence of shell commands below, the scaling_min_freq attribute for policy1 and policy2 should be affected in the same way, because scaling_governor is set in the same way for both of them: # cat cpufreq/policy1/scaling_governor powersave # cat cpufreq/policy2/scaling_governor powersave # echo performance > cpufreq/policy0/scaling_governor # echo 94 > intel_pstate/min_perf_pct # cat cpufreq/policy0/scaling_min_freq 2914000 # cat cpufreq/policy1/scaling_min_freq 2914000 # cat cpufreq/policy2/scaling_min_freq 800000 The are affected differently, because intel_pstate_verify_policy() is invoked with limits set to &performance_limits (left behind by policy0) for policy1 and with limits set to &powersave_limits (left behind by policy1) for policy2. Since perf_limits is set to the set of limits matching the policy being updated, using it instead of limits fixes the inconsistency. Fixes: 1443ebbacfd7 (cpufreq: intel_pstate: Fix sysfs limits enforcement for performance policy) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-03-06cpufreq: intel_pstate: Fix global settings in active modeRafael J. Wysocki
Commit 111b8b3fe4fa (cpufreq: intel_pstate: Always keep all limits settings in sync) changed intel_pstate to invoke cpufreq_update_policy() for every registered CPU on global sysfs attributes updates, but that led to undesirable effects in the active mode if the "performance" P-state selection algorithm is configufred for one CPU and the "powersave" one is chosen for all of the other CPUs. Namely, in that case, the following is possible: # cd /sys/devices/system/cpu/ # cat intel_pstate/max_perf_pct 100 # cat intel_pstate/min_perf_pct 26 # echo performance > cpufreq/policy0/scaling_governor # cat intel_pstate/max_perf_pct 100 # cat intel_pstate/min_perf_pct 100 # echo 94 > intel_pstate/min_perf_pct # cat intel_pstate/min_perf_pct 26 The reason why this happens is because intel_pstate attempts to maintain two sets of global limits in the active mode, one for the "performance" P-state selection algorithm and one for the "powersave" P-state selection algorithm, but the P-state selection algorithms are set per policy, so the global limits cannot reflect all of them at the same time if they are different for different policies. In the particular situation above, the attempt to change min_perf_pct to 94 caused cpufreq_update_policy() to be run for a CPU with the "powersave" P-state selection algorithm and intel_pstate_set_policy() called by it silently switched the global limits to the "powersave" set which finally was reflected by the sysfs interface. To prevent that from happening, modify intel_pstate_update_policies() to always switch back to the set of limits that was used right before it has been invoked. Fixes: 111b8b3fe4fa (cpufreq: intel_pstate: Always keep all limits settings in sync) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-03-06cpufreq: Add the "cpufreq.off=1" cmdline optionLen Brown
Add the "cpufreq.off=1" cmdline option. At boot-time, this allows a user to request CONFIG_CPU_FREQ=n behavior from a kernel built with CONFIG_CPU_FREQ=y. This is analogous to the existing "cpuidle.off=1" option and CONFIG_CPU_IDLE=y This capability is valuable when we need to debug end-user issues in the BIOS or in Linux. It is also convenient for enabling comparisons, which may otherwise require a new kernel, or help from BIOS SETUP, which may be buggy or unavailable. Signed-off-by: Len Brown <len.brown@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-03-04cpufreq: intel_pstate: Avoid triggering cpu_frequency tracepoint unnecessarilyRafael J. Wysocki
In the passive mode the cpu_frequency trace event is already triggered by the cpufreq core or by scaling governors, so intel_pstate should not trigger it once again for the same P-state updates. In addition to that, the frequency returned by intel_cpufreq_fast_switch() and passed via freqs.new from intel_cpufreq_target() to cpufreq_freq_transition_end() should reflect the P-state actually set, so make that happen. Fixes: 001c76f05b01 (cpufreq: intel_pstate: Generic governors support) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-03-04cpufreq: intel_pstate: Fix intel_cpufreq_verify_policy()Rafael J. Wysocki
The intel_pstate_update_perf_limits() called from intel_cpufreq_verify_policy() may cause global P-state limits to change which is generally confusing and unnecessary. In the passive mode the global limits are only applied to the frequency selected by the scaling governor (they are not taken into account by governors when making decisions anyway), so making them follow the per-policy limits serves no purpose and may go against user expectations (as it generally causes the global attributes in sysfs to change even though they have not been written to in some cases). Fix that by dropping the intel_pstate_update_perf_limits() invocation from intel_cpufreq_verify_policy() (which also reduces the code size by a few lines). This change does not affect the per-CPU limits case, because those limits allow any P-state to be set by default in the passive mode and it removes the only piece of code updating them in that mode, so the per-policy settings will be the only ones taken into account in that case as expected. Fixes: 001c76f05b01 (cpufreq: intel_pstate: Generic governors support) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-03-04cpufreq: intel_pstate: Do not use performance_limits in passive modeRafael J. Wysocki
Using performance_limits in the passive mode doesn't make sense, because in that mode the global limits are applied to the frequency selected by the scaling governor. The maximum and minimum P-state limits in performance_limits are both set to 100 percent which will put all CPUs into the turbo range regardless of what governor is used and what frequencies are selected by it (that is particularly undesirable on CPUs with the generic powersave governor attached). For this reason, make intel_pstate_register_driver() always point limits to powersave_limits in the passive mode. Fixes: 001c76f05b01 (cpufreq: intel_pstate: Generic governors support) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-03-03Merge branch 'WIP.sched-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull sched.h split-up from Ingo Molnar: "The point of these changes is to significantly reduce the <linux/sched.h> header footprint, to speed up the kernel build and to have a cleaner header structure. After these changes the new <linux/sched.h>'s typical preprocessed size goes down from a previous ~0.68 MB (~22K lines) to ~0.45 MB (~15K lines), which is around 40% faster to build on typical configs. Not much changed from the last version (-v2) posted three weeks ago: I eliminated quirks, backmerged fixes plus I rebased it to an upstream SHA1 from yesterday that includes most changes queued up in -next plus all sched.h changes that were pending from Andrew. I've re-tested the series both on x86 and on cross-arch defconfigs, and did a bisectability test at a number of random points. I tried to test as many build configurations as possible, but some build breakage is probably still left - but it should be mostly limited to architectures that have no cross-compiler binaries available on kernel.org, and non-default configurations" * 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (146 commits) sched/headers: Clean up <linux/sched.h> sched/headers: Remove #ifdefs from <linux/sched.h> sched/headers: Remove the <linux/topology.h> include from <linux/sched.h> sched/headers, hrtimer: Remove the <linux/wait.h> include from <linux/hrtimer.h> sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h> sched/headers, timers: Remove the <linux/sysctl.h> include from <linux/timer.h> sched/headers: Remove <linux/magic.h> from <linux/sched/task_stack.h> sched/headers: Remove <linux/sched.h> from <linux/sched/init.h> sched/core: Remove unused prefetch_stack() sched/headers: Remove <linux/rculist.h> from <linux/sched.h> sched/headers: Remove the 'init_pid_ns' prototype from <linux/sched.h> sched/headers: Remove <linux/signal.h> from <linux/sched.h> sched/headers: Remove <linux/rwsem.h> from <linux/sched.h> sched/headers: Remove the runqueue_is_locked() prototype sched/headers: Remove <linux/sched.h> from <linux/sched/hotplug.h> sched/headers: Remove <linux/sched.h> from <linux/sched/debug.h> sched/headers: Remove <linux/sched.h> from <linux/sched/nohz.h> sched/headers: Remove <linux/sched.h> from <linux/sched/stat.h> sched/headers: Remove the <linux/gfp.h> include from <linux/sched.h> sched/headers: Remove <linux/rtmutex.h> from <linux/sched.h> ...
2017-03-02Merge tag 'pm-turbostat-4.11-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull turbostat utility updates from Rafael Wysocki: "Power management turbostat utility updates. These update turbostat significantly and in particular: - default output is now verbose, --debug is no longer required to get all counters. As a result, some options have been added to specify exactly what output is wanted. - added --quiet to skip system configuration output - added --list, --show and --hide parameters - added --cpu parameter - enhanced Baytrail SoC support - added Gemini Lake SoC support - added sysfs C-state columns Also the symbol definitions in arch/x86/include/asm/intel-family.h and arch/x86/include/asm/msr-index.h are updated and the intel_idle and intel_pstate drivers are modified to use the updated symbols. Credits to Len Brown for all of these changes" * tag 'pm-turbostat-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (44 commits) tools/power turbostat: version 17.02.24 tools/power turbostat: bugfix: --add u32 was printed as u64 tools/power turbostat: show error on exec tools/power turbostat: dump p-state software config tools/power turbostat: show package number, even without --debug tools/power turbostat: support "--hide C1" etc. tools/power turbostat: move --Package and --processor into the --cpu option tools/power turbostat: turbostat.8 update tools/power turbostat: update --list feature tools/power turbostat: use wide columns to display large numbers tools/power turbostat: Add --list option to show available header names tools/power turbostat: fix zero IRQ count shown in one-shot command mode tools/power turbostat: add --cpu parameter tools/power turbostat: print sysfs C-state stats tools/power turbostat: extend --add option to accept /sys path tools/power turbostat: skip unused counters on BDX tools/power turbostat: fix decoding for GLM, DNV, SKX turbo-ratio limits tools/power turbostat: skip unused counters on SKX tools/power turbostat: Denverton: use HW CC1 counter, skip C3, C7 tools/power turbostat: initial Gemini Lake SOC support ...
2017-03-02Merge tag 'pm-extra-4.11-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull more power management updates deom Rafael Wysocki: "These fix two bugs introduced by recent power management updates (in the cpuidle menu governor and intel_pstate) and a few other issues, clean up things and remove unused code. Specifics: - Fix for a cpuidle menu governor problem that started to take an unnecessary spinlock after one of the recent updates and that did not play well with the RT patch (Rafael Wysocki). - Fix for the new intel_pstate operation mode switching feature added recently that did not reinitialize P-state limits properly when switching operation modes (Rafael Wysocki). - Removal of unused global notifiers from the PM QoS framework (Viresh Kumar). - Generic power domains framework update to make it handle asynchronous invocations of PM callbacks in the "noirq" phases of system suspend/hibernation correctly (Ulf Hansson). - Two hibernation core cleanups (Rafael Wysocki). - intel_idle cleanup related to the sysfs interface (Len Brown). - Off-by-one bug fix in the OPP (Operating Performance Points) framework (Andrzej Hajda). - OPP framework's documentation fix (Viresh Kumar). - cpufreq qoriq driver cleanup (Tang Yuantian). - Fixes for typos in comments in the device runtime PM framework (Christophe Jaillet)" * tag 'pm-extra-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: PM / OPP: Documentation: Fix opp-microvolt in examples intel_idle: stop exposing platform acronyms in sysfs cpufreq: intel_pstate: Fix limits issue with operation mode switching PM / hibernate: Define pr_fmt() and use pr_*() instead of printk() PM / hibernate: Untangle power_down() cpuidle: menu: Avoid taking spinlock for accessing QoS values PM / QoS: Remove global notifiers PM / runtime: Fix some typos cpufreq: qoriq: clean up unused code PM / OPP: fix off-by-one bug in dev_pm_opp_get_max_volt_latency loop PM / Domains: Power off masters immediately in the power off sequence PM / Domains: Rename is_async to one_dev_on for genpd_power_off() PM / Domains: Move genpd_power_off() above genpd_power_on()
2017-03-03Merge branches 'pm-cpuidle', 'pm-cpufreq' and 'pm-sleep'Rafael J. Wysocki
* pm-cpuidle: intel_idle: stop exposing platform acronyms in sysfs cpuidle: menu: Avoid taking spinlock for accessing QoS values * pm-cpufreq: cpufreq: intel_pstate: Fix limits issue with operation mode switching cpufreq: qoriq: clean up unused code * pm-sleep: PM / hibernate: Define pr_fmt() and use pr_*() instead of printk() PM / hibernate: Untangle power_down()
2017-03-02sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar
<linux/sched/cpufreq.h> We are going to split <linux/sched/cpufreq.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/cpufreq.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02sched/core: Remove the tsk_cpus_allowed() wrapperIngo Molnar
So the original intention of tsk_cpus_allowed() was to 'future-proof' the field - but it's pretty ineffectual at that, because half of the code uses ->cpus_allowed directly ... Also, the wrapper makes the code longer than the original expression! So just get rid of it. This also shrinks <linux/sched.h> a bit. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-01Merge branch 'turbostat' of ↵Rafael J. Wysocki
git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux Pull changes related to turbostat for v4.11 from Len Brown. * 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux: (44 commits) tools/power turbostat: version 17.02.24 tools/power turbostat: bugfix: --add u32 was printed as u64 tools/power turbostat: show error on exec tools/power turbostat: dump p-state software config tools/power turbostat: show package number, even without --debug tools/power turbostat: support "--hide C1" etc. tools/power turbostat: move --Package and --processor into the --cpu option tools/power turbostat: turbostat.8 update tools/power turbostat: update --list feature tools/power turbostat: use wide columns to display large numbers tools/power turbostat: Add --list option to show available header names tools/power turbostat: fix zero IRQ count shown in one-shot command mode tools/power turbostat: add --cpu parameter tools/power turbostat: print sysfs C-state stats tools/power turbostat: extend --add option to accept /sys path tools/power turbostat: skip unused counters on BDX tools/power turbostat: fix decoding for GLM, DNV, SKX turbo-ratio limits tools/power turbostat: skip unused counters on SKX tools/power turbostat: Denverton: use HW CC1 counter, skip C3, C7 tools/power turbostat: initial Gemini Lake SOC support ...
2017-03-01intel_pstate: use MSR_ATOM_RATIOS definitions from msr-index.hLen Brown
Originally, these MSRs were locally defined in this driver. Now the definitions are in msr-index.h -- use them. Signed-off-by: Len Brown <len.brown@intel.com>
2017-02-28cpufreq: intel_pstate: Fix limits issue with operation mode switchingRafael J. Wysocki
There is a problem with intel_pstate operation mode switching introduced by commit fb1fe1041c04 (cpufreq: intel_pstate: Operation mode control from sysfs), because the global sysfs limits are preserved across operation modes while per-policy limits are reinitialized from scratch on a mode switch and both sets of limits may get out of sync this way. Fix that by always reinitializing the global limits upon the registration of the driver. Fixes: fb1fe1041c04 (cpufreq: intel_pstate: Operation mode control from sysfs) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
2017-02-23Merge tag 'armsoc-fixes-nc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc Pull ARM SoC non-urgent fixes from Arnd Bergmann: "We sometimes collect non-critical fixes that come in during the later part of the merge window in a branch for the next release instead, and this is that contents for v4.11. Most of these are OMAP fixes, dealing with OMAP36/37 detection, quirks and setup. There's also some fixes for Davinci and a Kconfig fix for SCPI to only enable on ARM{,64}" * tag 'armsoc-fixes-nc' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: firmware: arm_scpi: Add hardware dependencies ARM: OMAP3: Fix SoC detection of OMAP36/37 Family ARM: OMAP5: Add HWMOD_SWSUP_SIDLE_ACT flag for UART ARM: dts: Fix compatible for ti81xx uarts for 8250 ARM: dts: Fix am335x and dm814x scm syscon to probe children ARM: OMAP2+: Fix init for multiple quirks for the same SoC ARM: dts: Fix omap3 off mode pull defines bus: da850-mstpri: fix my e-mail address ARM: davinci: da850: fix da850_set_pll0rate() ARM: davinci: da850: coding style fix
2017-02-23cpufreq: qoriq: clean up unused codeTang Yuantian
This snip code is not needed anymore since its user get_hard_smp_processor_id() has been removed. Signed-off-by: Tang Yuantian <yuantian.tang@nxp.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-20Merge tag 'pm-4.11-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management updates from Rafael Wysocki: "The majority of changes go into the Operating Performance Points (OPP) framework and cpufreq this time, followed by devfreq and some scattered updates all over. The OPP changes are mostly related to switching over from RCU-based synchronization, that turned out to be overly complicated and problematic, to reference counting using krefs. In the cpufreq land there are core cleanups, documentation updates, a new driver for Broadcom BMIPS SoCs, a new cpufreq-dt sub-driver for TI SoCs that require special handling, ARM64 SoCs support for the qoriq driver, intel_pstate updates, powernv driver update and assorted fixes. The devfreq changes are mostly fixes related to the sysfs interface and some Exynos drivers updates. Apart from that, the cpuidle menu governor will support per-CPU PM QoS constraints for the wakeup latency now, some bugs in the wakeup IRQs framework are fixed, the generic power domains framework should handle asynchronous invocations of *noirq suspend/resume callbacks from now on, the analyze_suspend.py script is updated and there is a new tool for intel_pstate diagnostics. Specifics: - Operating Performance Points (OPP) framework fixes, cleanups and switch over from RCU-based synchronization to reference counting using krefs (Viresh Kumar, Wei Yongjun, Dave Gerlach) - cpufreq core cleanups and documentation updates (Viresh Kumar, Rafael Wysocki) - New cpufreq driver for Broadcom BMIPS SoCs (Markus Mayer) - New cpufreq-dt sub-driver for TI SoCs requiring special handling, like in the AM335x, AM437x, DRA7x, and AM57x families, along with new DT bindings for it (Dave Gerlach, Paul Gortmaker) - ARM64 SoCs support for the qoriq cpufreq driver (Tang Yuantian) - intel_pstate driver updates including a new sysfs knob to control the driver's operation mode and fixes related to the no_turbo sysfs knob and the hardware-managed P-states feature support (Rafael Wysocki, Srinivas Pandruvada) - New interface to export ultra-turbo frequencies for the powernv cpufreq driver (Shilpasri Bhat) - Assorted fixes for cpufreq drivers (Arnd Bergmann, Dan Carpenter, Wei Yongjun) - devfreq core fixes, mostly related to the sysfs interface exported by it (Chanwoo Choi, Chris Diamand) - Updates of the exynos-bus and exynos-ppmu devfreq drivers (Chanwoo Choi) - Device PM QoS extension to support CPUs and support for per-CPU wakeup (device resume) latency constraints in the cpuidle menu governor (Alex Shi) - Wakeup IRQs framework fixes (Grygorii Strashko) - Generic power domains framework update including a fix to make it handle asynchronous invocations of *noirq suspend/resume callbacks correctly (Ulf Hansson, Geert Uytterhoeven) - Assorted fixes and cleanups in the core suspend/hibernate code, PM QoS framework and x86 ACPI idle support code (Corentin Labbe, Geert Uytterhoeven, Geliang Tang, John Keeping, Nick Desaulniers) - Update of the analyze_suspend.py script is updated to version 4.5 offering multiple improvements (Todd Brandt) - New tool for intel_pstate diagnostics using the pstate_sample tracepoint (Doug Smythies)" * tag 'pm-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (85 commits) MAINTAINERS: cpufreq: add bmips-cpufreq.c PM / QoS: Fix memory leak on resume_latency.notifiers PM / Documentation: Spelling s/wrtie/write/ PM / sleep: Fix test_suspend after sleep state rework cpufreq: CPPC: add ACPI_PROCESSOR dependency cpufreq: make ti-cpufreq explicitly non-modular cpufreq: Do not clear real_cpus mask on policy init tools/power/x86: Debug utility for intel_pstate driver AnalyzeSuspend: fix drag and zoom bug in javascript PM / wakeirq: report a wakeup_event on dedicated wekup irq PM / wakeirq: Fix spurious wake-up events for dedicated wakeirqs PM / wakeirq: Enable dedicated wakeirq for suspend cpufreq: dt: Don't use generic platdev driver for ti-cpufreq platforms cpufreq: ti: Add cpufreq driver to determine available OPPs at runtime Documentation: dt: add bindings for ti-cpufreq PM / OPP: Expose _of_get_opp_desc_node as dev_pm_opp API cpufreq: qoriq: Don't look at clock implementation details cpufreq: qoriq: add ARM64 SoCs support PM / Domains: Provide dummy governors if CONFIG_PM_GENERIC_DOMAINS=n cpufreq: brcmstb-avs-cpufreq: remove unnecessary platform_set_drvdata() ...
2017-02-20Merge branch 'sched-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "The main changes in this (fairly busy) cycle were: - There was a class of scheduler bugs related to forgetting to update the rq-clock timestamp which can cause weird and hard to debug problems, so there's a new debug facility for this: which uncovered a whole lot of bugs which convinced us that we want to keep the debug facility. (Peter Zijlstra, Matt Fleming) - Various cputime related updates: eliminate cputime and use u64 nanoseconds directly, simplify and improve the arch interfaces, implement delayed accounting more widely, etc. - (Frederic Weisbecker) - Move code around for better structure plus cleanups (Ingo Molnar) - Move IO schedule accounting deeper into the scheduler plus related changes to improve the situation (Tejun Heo) - ... plus a round of sched/rt and sched/deadline fixes, plus other fixes, updats and cleanups" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (85 commits) sched/core: Remove unlikely() annotation from sched_move_task() sched/autogroup: Rename auto_group.[ch] to autogroup.[ch] sched/topology: Split out scheduler topology code from core.c into topology.c sched/core: Remove unnecessary #include headers sched/rq_clock: Consolidate the ordering of the rq_clock methods delayacct: Include <uapi/linux/taskstats.h> sched/core: Clean up comments sched/rt: Show the 'sched_rr_timeslice' SCHED_RR timeslice tuning knob in milliseconds sched/clock: Add dummy clear_sched_clock_stable() stub function sched/cputime: Remove generic asm headers sched/cputime: Remove unused nsec_to_cputime() s390, sched/cputime: Remove unused cputime definitions powerpc, sched/cputime: Remove unused cputime definitions s390, sched/cputime: Make arch_cpu_idle_time() to return nsecs ia64, sched/cputime: Remove unused cputime definitions ia64: Convert vtime to use nsec units directly ia64, sched/cputime: Move the nsecs based cputime headers to the last arch using it sched/cputime: Remove jiffies based cputime sched/cputime, vtime: Return nsecs instead of cputime_t to account sched/cputime: Complete nsec conversion of tick based accounting ...
2017-02-16cpufreq: CPPC: add ACPI_PROCESSOR dependencyArnd Bergmann
Without the Kconfig dependency, we can get this warning: warning: ACPI_CPPC_CPUFREQ selects ACPI_CPPC_LIB which has unmet direct dependencies (ACPI && ACPI_PROCESSOR) Fixes: 5477fb3bd1e8 (ACPI / CPPC: Add a CPUFreq driver for use with CPPC) Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-16cpufreq: make ti-cpufreq explicitly non-modularPaul Gortmaker
The Kconfig currently controlling compilation of this code is: drivers/cpufreq/Kconfig.arm:config ARM_TI_CPUFREQ drivers/cpufreq/Kconfig.arm: bool "Texas Instruments CPUFreq support" ...meaning that it currently is not being built as a module by anyone. Lets remove the couple traces of modular infrastructure use, so that when reading the driver there is no doubt it is builtin-only. Since module_init translates to device_initcall in the non-modular case, the init ordering remains unchanged with this commit. We also delete the MODULE_LICENSE tag etc. since all that information is already contained at the top of the file in the comments. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-16cpufreq: Do not clear real_cpus mask on policy initRafael J. Wysocki
If new_policy is set in cpufreq_online(), the policy object has just been created and its real_cpus mask has been zeroed on allocation, and the driver's ->init() callback should not touch it. It doesn't need to be cleared again, so don't do that. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2017-02-09cpufreq: dt: Don't use generic platdev driver for ti-cpufreq platformsDave Gerlach
Some TI platforms, specifically those in the am33xx, am43xx, dra7xx, and am57xx families of SoCs can make use of the ti-cpufreq driver to selectively enable OPPs based on the exact configuration in use. The ti-cpufreq is given the responsibility of creating the cpufreq-dt platform device when the driver is in use so drop am33xx and dra7xx from the cpufreq-dt-platdev driver so it is not created twice. Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Dave Gerlach <d-gerlach@ti.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-09cpufreq: ti: Add cpufreq driver to determine available OPPs at runtimeDave Gerlach
Some TI SoCs, like those in the AM335x, AM437x, DRA7x, and AM57x families, have different OPPs available for the MPU depending on which specific variant of the SoC is in use. This can be determined through use of the revision and an eFuse register present in the silicon. Introduce a ti-cpufreq driver that can read the aformentioned values and provide them as version matching data to the opp framework. Through this the opp-supported-hw dt binding that is part of the operating-points-v2 table can be used to indicate availability of OPPs for each device. This driver also creates the "cpufreq-dt" platform_device after passing the version matching data to the OPP framework so that the cpufreq-dt handles the actual cpufreq implementation. Even without the necessary data to pass the version matching data the driver will still create this device to maintain backwards compatibility with operating-points v1 tables. Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Dave Gerlach <d-gerlach@ti.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-09Merge OPP material for v4.11 to satisfy dependencies.Rafael J. Wysocki
2017-02-09cpufreq: qoriq: Don't look at clock implementation detailsTang Yuantian
Get the CPU clock's potential parent clocks from the clock interface itself, rather than manually parsing the clocks property to find a phandle, looking at the clock-names property of that, and assuming that those are valid parent clocks for the cpu clock. This is necessary now that the clocks are generated based on the clock driver's knowledge of the chip rather than a fragile device-tree description of the mux options. We can now rely on the clock driver to ensure that the mux only exposes options that are valid. The cpufreq driver was currently being overly conservative in some cases -- for example, the "min_cpufreq = get_bus_freq()" restriction only applies to chips with erratum A-004510, and whether the freq_mask used on p5020 is needed depends on the actual frequencies of the PLLs (FWIW, p5040 has a similar limitation but its .freq_mask was zero) -- and the frequency mask mechanism made assumptions about particular parent clock indices that are no longer valid. Signed-off-by: Scott Wood <scottwood@nxp.com> Signed-off-by: Tang Yuantian <yuantian.tang@nxp.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-09cpufreq: qoriq: add ARM64 SoCs supportTang Yuantian
Add ARM64 config to Kconfig to enable CPU frequency feature on NXP ARM64 SoCs. Signed-off-by: Tang Yuantian <yuantian.tang@nxp.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-09cpufreq: brcmstb-avs-cpufreq: remove unnecessary platform_set_drvdata()Wei Yongjun
The driver core clears the driver data to NULL after device_release or on probe failure. Thus, it is not needed to manually clear the device driver data to NULL. Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-09cpufreq: s3c2416: double free on driver init error pathDan Carpenter
The "goto err_armclk;" error path already does a clk_put(s3c_freq->hclk); so this is a double free. Fixes: 34ee55075265 ([CPUFREQ] Add S3C2416/S3C2450 cpufreq driver) Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-09cpufreq: bmips-cpufreq: CPUfreq driver for Broadcom's BMIPS SoCsMarkus Mayer
Add the MIPS CPUfreq driver. This driver currently supports CPUfreq on BMIPS5xxx-based SoCs. Signed-off-by: Markus Mayer <mmayer@broadcom.com> Acked-by: Florian Fainelli <f.fainelli@gmail.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-09Merge back earlier cpufreq changes for v4.11.Rafael J. Wysocki
2017-02-06Merge branches 'pm-core-fixes' and 'pm-cpufreq-fixes'Rafael J. Wysocki
* pm-core-fixes: PM / runtime: Avoid false-positive warnings from might_sleep_if() * pm-cpufreq-fixes: cpufreq: intel_pstate: Disable energy efficiency optimization cpufreq: brcmstb-avs-cpufreq: properly retrieve P-state upon suspend cpufreq: brcmstb-avs-cpufreq: extend sysfs entry brcm_avs_pmap
2017-02-04cpufreq: intel_pstate: Disable energy efficiency optimizationSrinivas Pandruvada
Some Kabylake desktop processors may not reach max turbo when running in HWP mode, even if running under sustained 100% utilization. This occurs when the HWP.EPP (Energy Performance Preference) is set to "balance_power" (0x80) -- the default on most systems. It occurs because the platform BIOS may erroneously enable an energy-efficiency setting -- MSR_IA32_POWER_CTL BIT-EE, which is not recommended to be enabled on this SKU. On the failing systems, this BIOS issue was not discovered when the desktop motherboard was tested with Windows, because the BIOS also neglects to provide the ACPI/CPPC table, that Windows requires to enable HWP, and so Windows runs in legacy P-state mode, where this setting has no effect. Linux' intel_pstate driver does not require ACPI/CPPC to enable HWP, and so it runs in HWP mode, exposing this incorrect BIOS configuration. There are several ways to address this problem. First, Linux can also run in legacy P-state mode on this system. As intel_pstate is how Linux enables HWP, booting with "intel_pstate=disable" will run in acpi-cpufreq/ondemand legacy p-state mode. Or second, the "performance" governor can be used with intel_pstate, which will modify HWP.EPP to 0. Or third, starting in 4.10, the /sys/devices/system/cpu/cpufreq/policy*/energy_performance_preference attribute in can be updated from "balance_power" to "performance". Or fourth, apply this patch, which fixes the erroneous setting of MSR_IA32_POWER_CTL BIT_EE on this model, allowing the default configuration to function as designed. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Reviewed-by: Len Brown <len.brown@intel.com> Cc: 4.6+ <stable@vger.kernel.org> # 4.6+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-04cpufreq: intel_pstate: Calculate guaranteed performance for HWPSrinivas Pandruvada
When HWP is active, turbo activation ratio is not used to calculate max non turbo ratio. But on these systems the max non turbo ratio is decided by config TDP settings. This change removes usage of MSR_TURBO_ACTIVATION_RATIO for HWP systems, instead directly use TDP ratios, when more than one TDPs are available. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-04cpufreq: intel_pstate: Make HWP limits compatible with legacySrinivas Pandruvada
Under HWP the performance limits are calculated using max_perf_pct and min_perf_pct using possible performance, not available performance. The available performance can be reduced by no_turbo setting. To make compatible with legacy mode, use max/min performance percentage with respect to available performance. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-04cpufreq: intel_pstate: Lower frequency than expected under no_turboSrinivas Pandruvada
When turbo is not disabled by BIOS, but user disabled from intel P-State sysfs and changes max/min using cpufreq sysfs, the resultant frequency is lower than what user requested. The reason for this, when the perf limits are calculated in set_policy() callback, they are with reference to max cpu frequency (turbo frequency ), but when enforced in the intel_pstate_get_min_max() they are with reference to max available performance as documented in the intel_pstate documentation (in this case max non turbo P-State). This needs similar change as done in intel_cpufreq_verify_policy() for passive mode. Set policy->cpuinfo.max_freq based on the turbo status. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-04cpufreq: intel_pstate: Operation mode control from sysfsRafael J. Wysocki
Make it possible to change the operation mode of intel_pstate with the help of a new sysfs attribute called "status". There are three possible configurations that can be selected using this attribute: "off" - The driver is not in use at this time. "active" - The driver works as a P-state governor (default). "passive" - The driver works as a regular cpufreq one and collaborates with the generic cpufreq governors (it sets P-states as requested by those governors). [This is the same mode the driver can be started in by passing intel_pstate=passive in the kernel command line.] The current setting is returned by reads from this attribute. Writing one of the above strings to it changes the operation mode as indicated by that string, if possible. If HW-managed P-states (HWP) feature is enabled, it is not possible to change the driver's operation mode and attempts to write to this attribute will fail. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>