Bug 63580 – Default /dev/dri/card* permissions don't match between udev and X

• Status: RESOLVED UPSTREAM
• Product: Gentoo Linux

[Description Andrés Becerra Sandoval 2004-09-10 12:05:00 UTC]

Everytime I launch startx the permisions for /dev/dri/car0 are set to root:root and this doesn't allow to do Direct Rendering for non superusers. If I, manually, set the permissions to root:users  (chgrp users /dev/dri/card0), Direct Rendering works Ok as glxinfo reports.

Xorg version:  6.7.0-r1

Extract of emerge info output:
Portage 2.0.50-r10 (default-x86-1.4, gcc-3.3.4, glibc-2.3.3.20040420-r1, 2.6.8-gentoo-r3)
=================================================================
System uname: 2.6.8-gentoo-r3 i686 Intel(R) Pentium(R) 4 CPU 2.60GHz
Gentoo Base System version 1.4.16
Autoconf: sys-devel/autoconf-2.59-r4
Automake: sys-devel/automake-1.8.5-r1
ACCEPT_KEYWORDS="x86"
AUTOCLEAN="yes"
CFLAGS="-O3 -march=i686 -mcpu=pentium4 -funroll-loops -fprefetch-loop-arrays -pipe"
CHOST="i686-pc-linux-gnu"


Reproducible: Always
Steps to Reproduce:
1. startx from console
2. glxinfo

Actual Results:  
libGL error: failed to open DRM: Operation not permitted
libGL error: reverting to (slow) indirect rendering
display: :0  screen: 0
direct rendering: No


Expected Results:  
name of display: :0.0
display: :0  screen: 0
direct rendering: Yes

In bug 55833 is reported that everything in /dev/dri/* should belong to root:
users.

[Comment 1 Seemant Kulleen (RETIRED) 2004-09-10 12:42:17 UTC]

I thought this was something to be set in the xorg.conf file?

[Comment 2 Donnie Berkholz (RETIRED) 2004-10-11 00:23:30 UTC]

It is.

http://dri.sourceforge.net/cgi-bin/moin.cgi/Building has some info on this. 

For example, if you only want a certain group:
Section "DRI" 
    Group "driusers" 
    Mode 0660 
EndSection 

Otherwise, do mode 0666 and leave out the Group line.

[Comment 3 Petr Baudis 2005-09-11 09:56:33 UTC]

I believe that the group ownership should be 'video' instead of 'root' by
default, also in accordance with udev default settings: "dri/*:root:video:0660"

[Comment 4 Donnie Berkholz (RETIRED) 2005-09-11 12:49:06 UTC]

OK

[Comment 5 Donnie Berkholz (RETIRED) 2005-09-11 12:49:44 UTC]

File a bug at bugs.freedesktop.org and post the URL here.

[Comment 6 Petr Baudis 2005-09-11 12:53:58 UTC]

Does it really make sense to have that default in xorg itself? I mean, is the
"video" group universal? Also, so far I think stock xorg did not depend on any
particular user/group (except root) to be present on the system it install onto.

[Comment 7 Donnie Berkholz (RETIRED) 2005-09-11 13:06:44 UTC]

This isn't a per-distro issue, we don't want to be hacking around xorg and
adding custom patches. If you want it changed at all, you want it changed upstream.

[Comment 8 Petr Baudis 2005-09-11 14:08:16 UTC]

Filed as https://bugs.freedesktop.org/show_bug.cgi?id=4422

[Comment 9 Donnie Berkholz (RETIRED) 2005-09-11 20:28:16 UTC]

Thanks, Petr!

[Comment 10 Jakub Moc (RETIRED) 2006-03-13 01:38:24 UTC]

*** Bug 126026 has been marked as a duplicate of this bug. ***

[Comment 11 Honza 2007-10-01 10:03:39 UTC]

What about some comment in udev configuration for people who will want to change it and assume udev is doing it ?