diff options
| author | Emil Velikov <emil.velikov@collabora.com> | 2016-11-22 01:24:49 +0300 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2016-11-22 01:25:32 +0300 |
| commit | 702ed3be1b1bf4dea05954168321741c0910c645 (patch) | |
| tree | 4148dde5865bb993433dbf80be09d7a26b2121ca /Documentation | |
| parent | 1001354ca34179f3db924eb66672442a173147dc (diff) | |
| download | linux-702ed3be1b1bf4dea05954168321741c0910c645.tar.xz | |
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')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-pci | 7 | ||||
| -rw-r--r-- | Documentation/filesystems/sysfs-pci.txt | 2 |
2 files changed, 9 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. diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt index 74eaac26f8b8..6ea1ceda6f52 100644 --- a/Documentation/filesystems/sysfs-pci.txt +++ b/Documentation/filesystems/sysfs-pci.txt @@ -17,6 +17,7 @@ that support it. For example, a given bus might look like this: | |-- resource0 | |-- resource1 | |-- resource2 + | |-- revision | |-- rom | |-- subsystem_device | |-- subsystem_vendor @@ -41,6 +42,7 @@ files, each with their own function. resource PCI resource host addresses (ascii, ro) resource0..N PCI resource N, if present (binary, mmap, rw[1]) resource0_wc..N_wc PCI WC map resource N, if prefetchable (binary, mmap) + revision PCI revision (ascii, ro) rom PCI ROM resource, if present (binary, ro) subsystem_device PCI subsystem device (ascii, ro) subsystem_vendor PCI subsystem vendor (ascii, ro) |