xserver-xorg-video-amd 2.7.7.6-1ubuntu2 fails at DDC module on Flat Panel

[Asier]

Binary package hint: xserver-xorg-video-amd

I'm running Ubuntu Gutsy at fully upgraded to latest packages, plus updates to xserver-xorg-video-amd - 2.7.7.6-1ubuntu2 and xorg-server - 2:1.3.0.0.dfsg-12ubuntu12 from Martin-Éric Racine.
It's running on an AMD GEODE LX800 board, namely it's an ALX800-LCQE from Advansus. The board has a Phoenix Award BIOS.

Everything runs fine regarding the video driver as long as I run on a CRT screen. It also works with a dual display (CRT+TFT), but X fail to start when runing on TFT only.
The TFT panel has LVDS interface, and it is working properly at an intel board, and also at the amd board when used in conjunction with the CRT.

Looking at the Xorg.log it stops after loading the DDC module, while it is not the case if working together with a CRT.

Any idea on what I can look at?

Thanks in advance,
Asier.

[Miguel-costa (miguel-costa)]

Created an attachment (id=11843)
Log from broken system

[Miguel-costa (miguel-costa)]

Created an attachment (id=11844)
Conf from broken system

[Martin-Éric Racine (q-funk)]

The driver is broken with X server 1.3 or newer because it uses x86emu whereas all previous X servers used vm86. It affects BIOS polling in a number of ways.

[Martin-Éric Racine (q-funk)]

Note that driver version 2.7.7.5 introduced basic OLPC support. Please test this release on your laptop and report on your results.

[Asier (a-azaceta)]

Binary package hint: xserver-xorg-video-amd

I'm running Ubuntu Gutsy at fully upgraded to latest packages, plus updates to xserver-xorg-video-amd - 2.7.7.6-1ubuntu2 and xorg-server - 2:1.3.0.0.dfsg-12ubuntu12 from Martin-Éric Racine.
It's running on an AMD GEODE LX800 board, namely it's an ALX800-LCQE from Advansus. The board has a Phoenix Award BIOS.

Everything runs fine regarding the video driver as long as I run on a CRT screen. It also works with a dual display (CRT+TFT), but X fail to start when runing on TFT only.
The TFT panel has LVDS interface, and it is working properly at an intel board, and also at the amd board when used in conjunction with the CRT.

Looking at the Xorg.log it stops after loading the DDC module, while it is not the case if working together with a CRT.

Any idea on what I can look at?

Thanks in advance,
Asier.

[Martin-Éric Racine (q-funk)]

This should work with AMD driver 2.7.7.6 and an X server patched with https://bugs.freedesktop.org/show_bug.cgi?id=14332

Can you please confirm this?

[Martin-Éric Racine (q-funk)]

As I recall, DDC is not supported on TFT panel. On those, the driver really needs a static /etc/X11/xorg.conf to work.

[Martin-Éric Racine (q-funk)]

The driver is supposed to get information from the BIOS about which display type is connected. It uses that information to disable certain features such as DDC. Still, as a test, you might wanna add the Panel statement to the device section when running only TFT and see if this improves your results.

[Asier (a-azaceta)]

Thanks for the lead.
I tried with the panel related parameter without any success. After some research on the aforementioned panel statement and DDC not being supported on TFT, I found some people using DDC specific options in other drivers, so despite I didn't found these options in any info related to the video-amd driver, I tried the 'Option "NoDDC"' statement, and it worked!!
Now I have to tweak a bit the xorg.conf, but it's definitely working.

By the way, I've found quite difficult to find official documentation in the web about the options supported by the driver, counting only with a man page that didn't include the "NoDDC" option. Is it undocumented or is it just that I didn't find it?

Thanks a lot for your help Martin-Éric.
Keep the good work.

[Martin-Éric Racine (q-funk)]

Try the noDDC option described at https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-amd/+bug/195846 and see if it helps.

[Miguel-costa (miguel-costa)]

I'm sorry for not getting back regarding this laptop. At the time, I managed to get a working solution with a custom gdm script and ddcprobe to switch between X server layouts, although I could never acess the console (with ctrl-alt-f*), it always returned a white screen.

Following Martin-Éric's advice (comment #5), I upgraded to xserver-xorg-video-amd_2.7.7.6-1ubuntu2_i386 and xserver-xorg-core_1.3.0.0.dfsg-12ubuntu12_i386 (from ppa.launchpad.net/q-funk).

Both the output to panel and external monitor work now, with the amd driver, and switching to console and back also works, so I guess this means it's fixed.

[Bryce Harrington (bryce)]

According to upstream bug 12642 that this is linked to, the issue is resolved by the incorporation of two patches which have also been included in Ubuntu, so I assume this issue has been resolved? If not, please reopen.