X lockup while playing a video (VDPAU)

[Peter Cordes]

While playing a video with mpv, X locked up entirely (not even mouse movement did anything). Even kill -9 won't kill the X server, although /etc/init.d/sddm restart did get the video card to text mode. (But the Xorg process is stuck in state D.) Unfortunately this means I couldn't get a stack backtrace from Xorg, since gdb hangs while trying to attach.

This is the first time I've seen this flavour of lockup, and it happened soon after booting the latest kernel update for 15.10 (linux-image-4.2.0-41-g 4.2.0-41.48 amd64). (So this might actually be a DRM bug, but I'm reporting it on a graphics-specific package so the right people can see it and migrate it where it needs to go).

My hardware is an ATI HD4670, on an Intel c2duo (E6600) desktop (dg965wh motherboard). Both DVI outputs are in use, one for a 1680x1050 and the other for a 1920x1200 LCD.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: xserver-xorg-video-radeon 1:7.5.0+git20150819-0ubuntu1
ProcVersionSignature: Ubuntu 4.2.0-41.48-generic 4.2.8-ckt11
Uname: Linux 4.2.0-41-generic x86_64
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
Date: Tue Jul 12 01:53:26 2016
SourcePackage: xserver-xorg-video-ati
UpgradeStatus: Upgraded to wily on 2015-11-12 (242 days ago)

[penalvch (penalvch)]

Peter Cordes, thank you for reporting this and helping make Ubuntu better.

As per https://wiki.ubuntu.com/Releases 15.10 is EOL.

If you have an issue in a supported release (ex. 16.04) please file a new report, and feel free to subscribe me to it.