[fglrx] doesn't support DefaultDepth below 24, so fglrx generated xorg.conf won't boot

[Thomas Novin]

Binary package hint: xorg-driver-fglrx

After installing Hardy Alpha 4 I enabled fglrx from Driver Setup. It crashed and didn't get the job done. This is bug https://bugs.launchpad.net/bugs/186584.

I applied the patch proposed in that bug and was then able to enable / disable fglrx. Since my xorg.conf was completely screwed I ran as described in the file I had, 'sudo dpkg-reconfigure -phigh xserver-xorg'.

I enabled fglrx, noticed that my xorg.conf was updated and rebooted. X didn't start with this config though.

I'm attaching the produced xorg.conf and /var/log/Xorg.0.log.

[Gabriel Thörnblad (gabriel-thornblad)]

I can confirm this bug. I believe the description is somewhat misleading, though. As far as I know, the xorg.conf is supposed to be "bare-boned" in hardy to let xorg detect the hardware automatically. This is what fails horribly for me as well, with the same symptoms. X starts up in failsafe mode since no suitable configuration is found by the autodetection. My hardware is a Mobility Radeon X600 which is supposed to be supported by the latest fglrx driver and my screen is a Dell Laptop display at 1920x1200.
I have no real clue how the autodetection is supposed to work, but I guess that xresprobe is no longer used. Perhaps the output of ddcprobe and get-edid is of some help?

[Laurent Bigonville (bigon)]

try to add "DefaultDepth 24" in the screen section

[Thomas Novin (thomasn80)]

That helps. I guess X tries to start at a lower bpp (which is not supported by fglrx).

Now I only have these three bugs...

Cannot single click with external mouse:

https://bugs.launchpad.net/bugs/188351

Crashes when I add ServerLayout + 2 x InputDevice

https://bugs.launchpad.net/bugs/188869

I have no top panels if I don't do 'metacity --replace'

https://bugs.launchpad.net/bugs/188389

[Bryce Harrington (bryce)]

It seems it's apparently a well known issue that fglrx doesn't support 16 bit color depth:

 http://odin.prohosting.com/wedge01/gentoo-radeon-faq.html#4_16bit

I guess as a workaround xserver could be configured to not try 16 bit when flgrx is loaded, however really the true fix is for AMD/ATI to add better support for 16 bpp.

[Sander Jonkers (jonkers)]

I can confirm this bug, even in 8.04 Alpha 5. (The xorg.conf of Ubuntu 7.10 is OK.)

This bug is the root cause of the bugs reported on https://bugs.launchpad.net/ubuntu/+source/linux-restricted-modules-2.6.24/+bug/194963 and https://bugs.launchpad.net/ubuntu/+source/linux-restricted-modules-2.6.24/+bug/195918

Workaround by manually adding "Defaultdepth 24" to the the part "Section "Screen"" of the xorg.conf.

Very annoying bug. Please solve before 8.04 LTS.

I have the feeling the xorg.conf for ATI / fglrx is not (exclusively) written by dexconf nor /var/lib/dpkg/info/xserver-xorg.postinst, so it must be solved somewhere else.

[Sander Jonkers (jonkers)]

I have posted a patched fglrx.py + instruction on:

https://bugs.launchpad.net/ubuntu/+source/linux-restricted-modules-2.6.24/+bug/194963/comments/21

It solves two fglrx-xorg.conf problems for me:
1) no screen output due to the missing DefaultDepth 24
2) disabling Compiz because of the Composite 0 stuff in xorg.conf

Please note that you need to reboot after each change via jockey-gtk.

Please let me know if it works for you.

Disclaimer: I'm just a ubuntu user, not a ubuntu developer.