non-suid Xorg fails to start

[Sadako]

I'm trying to get xorg-server to run as user, ie without suid, but it's failing miserably.

This is with xorg-server-1.19.3, libdrm-2.4.76 and a 4.9.18 kernel, open radeon driver on a hd6670 (or something like that).

Not using systemd or any display manager, running startx.

Last few lines of Xorg.o.log;

Code: Select all

[183106.985] (II) RADEON(0): Output HDMI-0 connected
[183106.985] (II) RADEON(0): Output DVI-0 disconnected
[183106.985] (II) RADEON(0): Using exact sizes for initial modes
[183106.985] (II) RADEON(0): Output HDMI-0 using initial mode 1920x1080 +0+0
[183106.985] (II) RADEON(0): mem size init: gart size :3fddf000 vram size: s:40000000 visible:3f5d6000
[183106.985] (==) RADEON(0): DPI set to (96, 96)
[183106.985] (==) RADEON(0): Using gamma correction (1.0, 1.0, 1.0)
[183106.985] (II) Loading sub module "ramdac"
[183106.985] (II) LoadModule: "ramdac"
[183106.985] (II) Module "ramdac" already built-in
[183106.985] (II) UnloadModule: "modesetting"
[183106.985] (II) Unloading modesetting
[183106.985] (--) Depth 24 pixmap format is 32 bpp
[183106.985] Unable to retrieve master
[183106.985] (EE) 
Fatal server error:
[183106.985] (EE) AddScreen/ScreenInit failed for driver 0
[183106.985] (EE) 
[183106.985] (EE) 
Please consult the The X.Org Foundation support 
	 at http://wiki.x.org
 for help. 
[183106.985] (EE) Please also check the log file at "/home/sadako/.local/share/xorg/Xorg.0.log" for additional information.
[183106.985] (EE) 
[183106.991] (EE) Server terminated with error (1). Closing log file.

When xorg is run with suid set, this is what's in the log around the point where non-suid spits up 'Unable to retrieve master';

Code: Select all

[183229.615] (II) RADEON(0): Output HDMI-0 connected
[183229.615] (II) RADEON(0): Output DVI-0 disconnected
[183229.615] (II) RADEON(0): Using exact sizes for initial modes
[183229.615] (II) RADEON(0): Output HDMI-0 using initial mode 1920x1080 +0+0
[183229.615] (II) RADEON(0): mem size init: gart size :3fddf000 vram size: s:40000000 visible:3f5d6000
[183229.615] (==) RADEON(0): DPI set to (96, 96)
[183229.615] (==) RADEON(0): Using gamma correction (1.0, 1.0, 1.0)
[183229.615] (II) Loading sub module "ramdac"
[183229.615] (II) LoadModule: "ramdac"
[183229.615] (II) Module "ramdac" already built-in
[183229.615] (II) UnloadModule: "modesetting"
[183229.615] (II) Unloading modesetting
[183229.615] (--) Depth 24 pixmap format is 32 bpp
[183229.615] (II) RADEON(0): [DRI2] Setup complete
[183229.615] (II) RADEON(0): [DRI2]   DRI driver: r600
[183229.615] (II) RADEON(0): [DRI2]   VDPAU driver: r600
[183229.615] (II) RADEON(0): Front buffer size: 8640K
[183229.615] (II) RADEON(0): VRAM usage limit set to 926488K
[183229.615] (II) RADEON(0): SYNC extension fences enabled
[183229.615] (II) RADEON(0): Present extension enabled
[183229.615] (==) RADEON(0): DRI3 enabled
[183229.615] (==) RADEON(0): Backing store enabled
[183229.615] (II) RADEON(0): Direct rendering enabled
[183229.650] (II) RADEON(0): Use GLAMOR acceleration.
[183229.650] (II) RADEON(0): Acceleration enabled

Anyone have any ideas?

Anyone have xorg running without suid with radeon graphics?

Thanks.

edit: forgot to mention, user is in video group, and (temporarily) input group, too

[fedeliallalinea]

I never tested xorg without suid, but you followed this guide?

[Sadako]

I never tested xorg without suid, but you followed this guide?

Yep.

I had it working on my (now dead) laptop with intel graphics for about 4 years, but I couldn't get it working on my desktop with the radeon at that time, however a good bit of work has gone into xorg-server to make this work since then, largely due to the old security vulnerabilities revealed in the server in recent years.

Researching it online, looks to be an issue with xf86-video-ati specifically, gonna try the generic xf86-video-modesetting in a bit to confirm.

Supposedly it works just fine under systemd, so I'm pretty sure it not working otherwise is a bug.