Comment 6 for bug 1763273

Further debugging today while I'm on-site with the kiosks. The system froze, as usual, after normal idle screen blanking. I was able to login via ssh and retrieve some details.

First, it appears that the basic screen blanking problem is somehow related to the Radeon driver. I will attach the Xorg.0.log file and a gdb backtrace on the running but non-responsive Xorg process. No keyboard or mouse activity will un-blank the screen.

Here's the output from lspci | grep VGA:

01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RV516
[Radeon X1300/X1550 Series]

I'll also attach the PCI ROM dump from the /sys/devices rom file for this device.

This suggests that when we use Alt-SysRq-k to restore the system, sometimes we trigger *another* bug in the driver which results in the overall system crash. See the attached apr1.full.kern.log file for what details I could recover from the crash on April 1st; that corresponds to the screen photo I took that day (the radeon_kernel_panic1.jpg attachment).

The Xorg "hang" bug which precedes this appears similar, but not identical, to what is documented in #1664979:

https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1664979

I will continue to try to study the live Xorg process to see if I can determine where its hung, but I may not have time this evening. Let me know if there are specific further debugging steps I can take to examine either the Xorg hang or the subsequent crash which (sometimes) follows on attempting to recover with Alt-SysRq-k. (And note that I'll copy in the files apport-bug generated from #1764211 later tonight, using my "cdarroch" personal account, and then I'll try to close that extra bug report.)

Thanks very much,
Chris.