While I using the computer, the kernel of the system froze. I read the
/var/log/kern.log, finding that it might be a problem on VGA.
I attached the kern.log. Here's the important part:
Jan 25 19:34:24 debian kernel: [ 99.236022] [drm:i915_hangcheck_elapsed]
*ERROR* Hangcheck timer elapsed... GPU hung
Jan 25 19:34:24 debian kernel: [ 99.236035] [drm] capturing error event;
look for more information in /debug/dri/0/i915_error_state
Jan 25 19:34:31 debian kernel: [ 106.324022]
[drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... GPU hung
Jan 25 19:34:37 debian kernel: [ 112.148018]
[drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... GPU hung
Jan 25 19:34:37 debian kernel: [ 112.149387] [drm:i915_wait_request]
*ERROR* i915_wait_request returns -11 (awaiting 926 at 891, next 927)
It might have been a problem of kernel or Xorg.
Kernel version: 2.6.39-bpo.2-686-pae
Xorg version: 7.6+8~bpo60+1
xserver-xorg-video-intel: 2.15.0-3~bpo60+2