FS#4502 - udev/dri race condition

Attached to Project: Arch Linux
Opened by Simon Morgan (sjmorgan) - Monday, 24 April 2006, 11:27 GMT
Last edited by Tobias Powalowski (tpowa) - Monday, 24 April 2006, 12:22 GMT
Task Type Bug Report
Category Packages: Current
Status Closed
Assigned To Jan de Groot (JGC)
Architecture not specified
Severity Low
Priority Normal
Reported Version 0.7.1 Noodle
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 0
Private No

Details

Despite having Mode 0666 in the DRI sectiong of my xorg.conf, the first time Xorg is started DRI is disabled:

$ glxinfo
libGL error: open DRM failed (Operation not permitted)
libGL error: reverting to (slow) indirect rendering
display: :0 screen: 0
direct rendering: No
<snip>

I'm assuming this is because of:

crw-rw---- 1 root video 226, 0 2006-04-16 11:22 /dev/dri/card0

Restarting Xorg "fixes" the problem:

crw-rw-rw- 1 root root 226, 0 2006-04-16 11:22 /dev/dri/card0

It looks like by the time the device node is created, the part of Xorg that sets the permissions for it has already finished executing.
This task depends upon

Closed by  Jan de Groot (JGC)
Monday, 24 April 2006, 12:32 GMT
Reason for closing:  Won't fix
Comment by Jan de Groot (JGC) - Monday, 24 April 2006, 11:45 GMT
Making sure you're in the "video" group would actually "solve" this problem too.
Comment by Jan de Groot (JGC) - Monday, 24 April 2006, 12:32 GMT
What happens is this:
- Xorg starts
- Xorg loads the DRM driver
- Xorg sets permissions
- udev sets permissions

Three workarounds:
- Load your videocard module from MODULES (be sure to load the AGP module you need before it)
- Change udev permissions for /dev/dri things
- Put yourself in the video group

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