GPU Hang on i386 / i915GM with Firefox

[gsutre]

Opening several Firefox windows easily triggers the dreaded inteldrm0: gpu hung! error. The problem occurs on a Fujitsu Siemens Lifebook P7120 with the following setup:

• NetBSD/i386 (6.99.16), releng snapshot 201302101340Z.
• Pkgsrc package firefox-18.0.2 build from source.
• Installation of netbsd-drmgem with autobuild.sh -mv 201302101340Z.
• Graphics chipset: Intel 915GM.

The problem can be systematically triggered as follows:

1. Start the X server with startx and let twm initialize the session.
2. Launch firefox and open a second Firefox window (with Ctrl-N).
3. Load file:///usr/bin/ in the first window and file:///usr/lib/ in the second window.
4. Switch back and forth between the two windows (by left-clicking on the title bar) and move them around.
5. The X server freezes for a bit, and the message inteldrm0: gpu hung! appears in the kernel log.

As for issue #2, using DebugWait works around this problem.

Notes

• A netbsd-drmgem kernel with a vanilla X server does not exhibit the problem.
• This issue was already present in the first netbsd-drmgem release.
• The problem does not occur on another laptop with an Ironlake chipset (and NetBSD/amd64).

  /var/log/messages

/netbsd: inteldrm0: gpu hung!
/netbsd: _fault: failed to set to gtt (5)
/netbsd: inteldrm_fault: failed to set to gtt (5)
syslogd[356]: last message repeated 797 times
/netbsd: error: [drm:pid171:i915_gem_cleanup_ringbuffer] *ERROR* failed to quiesce ring buffer whilst cleaning up: 16

/var/log/Xorg.0.log

[    84.456] (EE) intel(0): Detected a hung GPU, disabling acceleration.