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author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2017-07-26 13:23:10 +0200 |
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committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2017-07-26 13:43:33 +0200 |
commit | af055598542670c8533a58582813b1419949cae0 (patch) | |
tree | 901fa1bf635d5c1e91d08f9f4c2e4943516dbb71 /Documentation/ABI/testing/sysfs-uevent | |
parent | drm/syncobj: Fix kerneldoc (diff) | |
parent | Merge tag 'drm-intel-next-2017-07-17' of git://anongit.freedesktop.org/git/drm-intel into drm-next (diff) | |
download | linux-dev-af055598542670c8533a58582813b1419949cae0.tar.xz linux-dev-af055598542670c8533a58582813b1419949cae0.zip |
Merge airlied/drm-next into drm-misc-next
I need this to be able to apply the deferred fbdev setup patches, I
need the relevant prep work that landed through the drm-intel tree.
Also squash in conflict fixup from Laurent Pinchart.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'Documentation/ABI/testing/sysfs-uevent')
-rw-r--r-- | Documentation/ABI/testing/sysfs-uevent | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-uevent b/Documentation/ABI/testing/sysfs-uevent new file mode 100644 index 000000000000..aa39f8d7bcdf --- /dev/null +++ b/Documentation/ABI/testing/sysfs-uevent @@ -0,0 +1,47 @@ +What: /sys/.../uevent +Date: May 2017 +KernelVersion: 4.13 +Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> +Description: + Enable passing additional variables for synthetic uevents that + are generated by writing /sys/.../uevent file. + + Recognized extended format is ACTION [UUID [KEY=VALUE ...]. + + The ACTION is compulsory - it is the name of the uevent action + ("add", "change", "remove"). There is no change compared to + previous functionality here. The rest of the extended format + is optional. + + You need to pass UUID first before any KEY=VALUE pairs. + The UUID must be in "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx" + format where 'x' is a hex digit. The UUID is considered to be + a transaction identifier so it's possible to use the same UUID + value for one or more synthetic uevents in which case we + logically group these uevents together for any userspace + listeners. The UUID value appears in uevent as + "SYNTH_UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx" environment + variable. + + If UUID is not passed in, the generated synthetic uevent gains + "SYNTH_UUID=0" environment variable automatically. + + The KEY=VALUE pairs can contain alphanumeric characters only. + It's possible to define zero or more pairs - each pair is then + delimited by a space character ' '. Each pair appears in + synthetic uevent as "SYNTH_ARG_KEY=VALUE". That means the KEY + name gains "SYNTH_ARG_" prefix to avoid possible collisions + with existing variables. + + Example of valid sequence written to the uevent file: + + add fe4d7c9d-b8c6-4a70-9ef1-3d8a58d18eed A=1 B=abc + + This generates synthetic uevent including these variables: + + ACTION=add + SYNTH_ARG_A=1 + SYNTH_ARG_B=abc + SYNTH_UUID=fe4d7c9d-b8c6-4a70-9ef1-3d8a58d18eed +Users: + udev, userspace tools generating synthetic uevents |