diff options
| author | Keith Busch <keith.busch@intel.com> | 2019-05-01 08:29:42 -0600 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2019-05-02 08:34:32 -0500 |
| commit | 2078e1e7f7e0e21bd0291908f3037c39e666d27b (patch) | |
| tree | a9b726e7f543d09fbfb3afe36f4349b011d2e434 | |
| parent | 15d2aba7c602cd9005b20ff011b670547b3882c4 (diff) | |
PCI/LINK: Add Kconfig option (default off)
e8303bb7a75c ("PCI/LINK: Report degraded links via link bandwidth
notification") added dmesg logging whenever a link changes speed or width
to a state that is considered degraded. Unfortunately, it cannot
differentiate signal integrity-related link changes from those
intentionally initiated by an endpoint driver, including drivers that may
live in userspace or VMs when making use of vfio-pci. Some GPU drivers
actively manage the link state to save power, which generates a stream of
messages like this:
vfio-pci 0000:07:00.0: 32.000 Gb/s available PCIe bandwidth, limited by 2.5 GT/s x16 link at 0000:00:02.0 (capable of 64.000 Gb/s with 5 GT/s x16 link)
Since we can't distinguish the intentional changes from the signal
integrity issues, leave the reporting turned off by default. Add a Kconfig
option to turn it on if desired.
Fixes: e8303bb7a75c ("PCI/LINK: Report degraded links via link bandwidth notification")
Link: https://lore.kernel.org/linux-pci/20190501142942.26972-1-keith.busch@intel.com
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
| -rw-r--r-- | drivers/pci/pcie/Kconfig | 8 | ||||
| -rw-r--r-- | drivers/pci/pcie/Makefile | 2 | ||||
| -rw-r--r-- | drivers/pci/pcie/portdrv.h | 4 |
3 files changed, 13 insertions, 1 deletions
diff --git a/drivers/pci/pcie/Kconfig b/drivers/pci/pcie/Kconfig index 5cbdbca904ac..362eb8cfa53b 100644 --- a/drivers/pci/pcie/Kconfig +++ b/drivers/pci/pcie/Kconfig @@ -142,3 +142,11 @@ config PCIE_PTM This is only useful if you have devices that support PTM, but it is safe to enable even if you don't. + +config PCIE_BW + bool "PCI Express Bandwidth Change Notification" + depends on PCIEPORTBUS + help + This enables PCI Express Bandwidth Change Notification. If + you know link width or rate changes occur only to correct + unreliable links, you may answer Y. diff --git a/drivers/pci/pcie/Makefile b/drivers/pci/pcie/Makefile index f1d7bc1e5efa..efb9d2e71e9e 100644 --- a/drivers/pci/pcie/Makefile +++ b/drivers/pci/pcie/Makefile @@ -3,7 +3,6 @@ # Makefile for PCI Express features and port driver pcieportdrv-y := portdrv_core.o portdrv_pci.o err.o -pcieportdrv-y += bw_notification.o obj-$(CONFIG_PCIEPORTBUS) += pcieportdrv.o @@ -13,3 +12,4 @@ obj-$(CONFIG_PCIEAER_INJECT) += aer_inject.o obj-$(CONFIG_PCIE_PME) += pme.o obj-$(CONFIG_PCIE_DPC) += dpc.o obj-$(CONFIG_PCIE_PTM) += ptm.o +obj-$(CONFIG_PCIE_BW) += bw_notification.o diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h index 1d50dc58ac40..944827a8c7d3 100644 --- a/drivers/pci/pcie/portdrv.h +++ b/drivers/pci/pcie/portdrv.h @@ -49,7 +49,11 @@ int pcie_dpc_init(void); static inline int pcie_dpc_init(void) { return 0; } #endif +#ifdef CONFIG_PCIE_BW int pcie_bandwidth_notification_init(void); +#else +static inline int pcie_bandwidth_notification_init(void) { return 0; } +#endif /* Port Type */ #define PCIE_ANY_PORT (~0) |