This random freeze has been happening for months now. I believe the problem is in the Direct Rendering Manager (DRM).
From kernel log:
dalius@PC1124:~$ cat /var/log/kern.log | grep drm
Sep 8 17:23:44 PC1124 kernel: [ 25.515278] [drm] Initialized drm 1.1.0 20060810
Sep 8 17:23:44 PC1124 kernel: [ 26.027712] [drm] Memory usable by graphics device = 2048M
Sep 8 17:23:44 PC1124 kernel: [ 26.027719] fb: conflicting fb hw usage inteldrmfb vs VESA VGA - removing generic driver
Sep 8 17:23:44 PC1124 kernel: [ 26.072105] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
Sep 8 17:23:44 PC1124 kernel: [ 26.072108] [drm] Driver supports precise vblank timestamp query.
Sep 8 17:23:45 PC1124 kernel: [ 26.190925] fbcon: inteldrmfb (fb0) is primary device
Sep 8 17:23:45 PC1124 kernel: [ 26.265140] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
Sep 8 17:23:45 PC1124 kernel: [ 26.265742] [drm] Initialized i915 1.6.0 20080730 for 0000:00:02.0 on minor 0
Sep 8 18:21:25 PC1124 kernel: [ 3497.804013] [drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... render ring idle
Sep 9 09:12:37 PC1124 kernel: [ 36.280400] [drm] Initialized drm 1.1.0 20060810
Sep 9 09:12:37 PC1124 kernel: [ 36.535447] [drm] Memory usable by graphics device = 2048M
Sep 9 09:12:37 PC1124 kernel: [ 36.535454] fb: conflicting fb hw usage inteldrmfb vs VESA VGA - removing generic driver
Sep 9 09:12:37 PC1124 kernel: [ 36.592545] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
Sep 9 09:12:37 PC1124 kernel: [ 36.592547] [drm] Driver supports precise vblank timestamp query.
Sep 9 09:12:37 PC1124 kernel: [ 36.711561] fbcon: inteldrmfb (fb0) is primary device
Sep 9 09:12:37 PC1124 kernel: [ 36.789513] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
Sep 9 09:12:37 PC1124 kernel: [ 36.791186] [drm] Initialized i915 1.6.0 20080730 for 0000:00:02.0 on minor 0
Sep 10 09:11:10 PC1124 kernel: [ 35.714929] [drm] Initialized drm 1.1.0 20060810
Sep 10 09:11:10 PC1124 kernel: [ 35.887189] [drm] Memory usable by graphics device = 2048M
Sep 10 09:11:10 PC1124 kernel: [ 35.887199] fb: conflicting fb hw usage inteldrmfb vs VESA VGA - removing generic driver
Sep 10 09:11:10 PC1124 kernel: [ 35.932129] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
Sep 10 09:11:10 PC1124 kernel: [ 35.932131] [drm] Driver supports precise vblank timestamp query.
Sep 10 09:11:10 PC1124 kernel: [ 36.060649] fbcon: inteldrmfb (fb0) is primary device
Sep 10 09:11:10 PC1124 kernel: [ 36.137382] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
Sep 10 09:11:10 PC1124 kernel: [ 36.147893] [drm] Initialized i915 1.6.0 20080730 for 0000:00:02.0 on minor 0
Sep 11 08:34:45 PC1124 kernel: [84264.804020] [drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... render ring idle
Sep 11 09:07:46 PC1124 kernel: [ 24.695604] [drm] Initialized drm 1.1.0 20060810
Sep 11 09:07:47 PC1124 kernel: [ 25.412141] [drm] Memory usable by graphics device = 2048M
Sep 11 09:07:47 PC1124 kernel: [ 25.412150] fb: conflicting fb hw usage inteldrmfb vs VESA VGA - removing generic driver
Sep 11 09:07:47 PC1124 kernel: [ 25.456089] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
Sep 11 09:07:47 PC1124 kernel: [ 25.456092] [drm] Driver supports precise vblank timestamp query.
Sep 11 09:07:47 PC1124 kernel: [ 25.574852] fbcon: inteldrmfb (fb0) is primary device
Sep 11 09:07:47 PC1124 kernel: [ 25.649351] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
Sep 11 09:07:47 PC1124 kernel: [ 25.649523] [drm] Initialized i915 1.6.0 20080730 for 0000:00:02.0 on minor 0
The freeze happens on these:
dalius@PC1124:~$ cat /var/log/kern.log | grep drm | grep hang
Sep 8 18:21:25 PC1124 kernel: [ 3497.804013] [drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... render ring idle
Sep 11 08:34:45 PC1124 kernel: [84264.804020] [drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... render ring idle
After this, I can't switch to tty1-tty6. I mostly see frozen login screen, but this has happened during normal usage (mostly while using alt+tab). Only solution is to hard reboot. I've found out about REISUB and will try it next time this happens.
Asus P5G41T-M LX2/GB (Integrated Intel GMA X4500 graphics)
Intel(R) Celeron(R) CPU E3400
Full HW info: http://pastebin.com/JSuVy8CU
Any suggestions on how to resolve/further debug this issue appreciated.