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authorEmil Velikov <emil.velikov@collabora.com>2016-11-21 16:24:49 -0600
committerBjorn Helgaas <bhelgaas@google.com>2016-11-21 16:25:32 -0600
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tree4148dde5865bb993433dbf80be09d7a26b2121ca /Documentation/ABI
parent1001354ca34179f3db924eb66672442a173147dc (diff)
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PCI: Create revision file in sysfs
Currently the revision isn't available via sysfs/libudev thus if one wants to know the value one needs to read through the config file, which can be quite time-consuming because it wakes/powers up the device. There are at least two userspace components which could make use the new file: libpciaccess and libdrm. The former wakes up _every_ PCI device, which can be observed via glxinfo when using Mesa 10.0+ drivers. The latter, in association with Mesa 13.0, can lead to 2-3 second delays while starting firefox, thunderbird or chromium. Link: https://bugs.freedesktop.org/show_bug.cgi?id=98502 Tested-by: Mauro Santos <registo.mailling@gmail.com> Signed-off-by: Emil Velikov <emil.velikov@collabora.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch CC: Greg KH <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/ABI')
-rw-r--r--Documentation/ABI/testing/sysfs-bus-pci7
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index b3bc50f650ee..5a1732b78707 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -294,3 +294,10 @@ Description:
a firmware bug to the system vendor. Writing to this file
taints the kernel with TAINT_FIRMWARE_WORKAROUND, which
reduces the supportability of your system.
+
+What: /sys/bus/pci/devices/.../revision
+Date: November 2016
+Contact: Emil Velikov <emil.l.velikov@gmail.com>
+Description:
+ This file contains the revision field of the the PCI device.
+ The value comes from device config space. The file is read only.