https://bugs.freedesktop.org/show_bug.cgi?id=44772

Bug #: 44772 Summary: Radeon HD6950 (Cayman): Resuming from hibernation fails sometimes Classification: Unclassified Product: DRI Version: XOrg CVS Platform: All OS/Version: Linux (All) Status: NEW Severity: major Priority: medium Component: DRM/Radeon AssignedTo: dri-devel@lists.freedesktop.org ReportedBy: h.judt@gmx.at

Resuming after hibernation fails sometimes. After reading the snapshot (the percentage reached 100%), the screen would switch back, but instead the monitor goes black and turns off and the complete system hangs. No ssh or sysreq keys work, everything is dead.

Some things I noticed that might help: * It does not occur with nomodeset=1. * You don't need X to reproduce this, just console with modesetting enabled is enough. * It is not reproducible reliably, but the likelyness that it will occur is unfortunately not small (I'd say 3-4 out of 10 attempts). * The fastboot kernel parameter is not related to it.

That is all with vanilla kernel. Now enter tuxonice, because it provides more information. Tuxonice reads the atomic copy first (20%..40%..60%..80%->100%). Now, it would switch on tuxoniceui and show the progress for reading in the caches. However, in the problem case the switch does not happen, because the system hangs as described for the vanilla kernel (no ssh, sysreq). At this point, one has to push the reset button to reboot. However, tuxonice has a nice feature: It will detect the image, and that it has resumed from this image before. It then asks the user whether he wants to try resuming from that same image again or remove the image and continue booting. If one presses 'C' to resume from the image, this time everything works and the system is fully functional. In fact, it's a 100% chance that the screen does not get black or the system freezes.

The issue does not occur at certain cycles, sometimes three hibernation->resume cycles go well, then the fourth and fifth will not work, then the next four are ok and so on...

So, I believe there is some issue with hardware initialization and hibernation. It might be that something does not really finish in time. What could there be wrong?

This is with vanilla-3.2-rc5 and 3.2-rc7-tuxonice (see http://git.tuxonice.net/?p=tuxonice-head.git;a=summary), but I guess all 3.2-rc kernels will show the same problem. I had troubles hibernating with vanilla-3.2-final, so I could not test this.