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linux/drivers/pci/pcie
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Keith Busch 2078e1e7f7 PCI/LINK: Add Kconfig option (default off) 
e8303bb7a7 ("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: e8303bb7a7 ("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>
2019-05-02 08:34:32 -05:00
..
aer_inject.c PCI/AER: Refactor error injection fallbacks 2018-10-18 19:43:19 -05:00
aer.c PCI/AER: Use match_string() helper to simplify the code 2019-01-29 16:32:17 -06:00
aspm.c pci-v4.21-changes 2019-01-05 17:57:34 -08:00
bw_notification.c PCI/LINK: Deduplicate bandwidth reports for multi-function devices 2019-03-25 17:59:07 -05:00
dpc.c PCI/DPC: Fix print AER status in DPC event handling 2019-02-21 17:07:20 -06:00
err.c PCI/ERR: Remove duplicated include from err.c 2018-10-02 16:04:40 -05:00
Kconfig PCI/LINK: Add Kconfig option (default off) 2019-05-02 08:34:32 -05:00
Makefile PCI/LINK: Add Kconfig option (default off) 2019-05-02 08:34:32 -05:00
pme.c PCI/PME: Fix possible use-after-free on remove 2019-03-01 17:45:27 -06:00
portdrv_core.c PCI/portdrv: Use shared MSI/MSI-X vector for Bandwidth Management 2019-05-01 15:34:01 -05:00
portdrv_pci.c PCI/LINK: Report degraded links via link bandwidth notification 2019-03-05 15:04:13 -06:00
portdrv.h PCI/LINK: Add Kconfig option (default off) 2019-05-02 08:34:32 -05:00
ptm.c Merge branch 'pci/spdx' into next 2018-02-01 11:40:07 -06:00