Created attachment 118646 [details]
dmesg output

Created attachment 118647 [details]
lspci output

Created attachment 118648 [details]
lshw output

Created attachment 118934 [details]
new dmesg output

Created attachment 118935 [details]
new gpu crash dumb

I reproduced the hang by playing HTML5 videos in Firefox. There are new lines that did not show up when I opened the bug report. I attached new GPU crash dump and dmesg output.

glxinfo | grep "OpenGL renderer string"
OpenGL renderer string: Mesa DRI Intel(R) Sandybridge Mobile 

glxinfo | grep "OpenGL version string"
OpenGL version string: 3.0 Mesa 11.0.3

LC_ALL=C pacman -Qi xf86-video-intel
Name           : xf86-video-intel
Version        : 1:2.99.917+478+gdf72bc5-2

LC_ALL=C pacman -Qi mesa
Name           : mesa
Version        : 11.0.3-1

LC_ALL=C pacman -Qi libdrm
Name           : libdrm
Version        : 2.4.65-1

LC_ALL=C sudo pacman -Qi xorg-server
Name           : xorg-server
Version        : 1.17.2-4

LC_ALL=C sudo pacman -Qi firefox
Name           : firefox
Version        : 41.0.2-1

uname -a
Linux dem 4.2.3-1-ARCH #1 SMP PREEMPT Sat Oct 3 18:52:50 CEST 2015 x86_64 GNU/Linux

lspci -d ::0300 -nn
00:02.0 VGA compatible controller [0300]: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0116] (rev 09)

grep "model name" /proc/cpuinfo | head -1
model name	: Intel(R) Core(TM) i3-2330M CPU @ 2.20GHz


[19525.559979] [drm] GPU HANG: ecode 6:0:0x87e8fffd, in MediaPl~back #7 [4677], reason: Ring hung, action: reset
[19525.561899] drm/i915: Resetting chip after gpu hang
[20444.503477] [drm] stuck on render ring
[20444.504549] [drm] GPU HANG: ecode 6:0:0x87e8fffd, in MediaPl~ack #18 [5713], reason: Ring hung, action: reset
[20444.506540] drm/i915: Resetting chip after gpu hang
[20579.643376] [drm] stuck on render ring
[20579.644452] [drm] GPU HANG: ecode 6:0:0x87e8fffd, in MediaPl~ack #19 [5724], reason: Ring hung, action: reset
[20579.646437] drm/i915: Resetting chip after gpu hang
[20741.817936] [drm] stuck on render ring
[20741.819005] [drm] GPU HANG: ecode 6:0:0x87e8fffd, in MediaPl~ack #16 [5714], reason: Ring hung, action: reset
[20741.821027] drm/i915: Resetting chip after gpu hang
[21290.365846] [drm] stuck on render ring
[21290.366448] [drm] GPU HANG: ecode 6:0:0x87e8fffd, in Xorg [571], reason: Ring hung, action: reset
[21290.368553] drm/i915: Resetting chip after gpu hang
[22555.708931] [drm] stuck on render ring
[22555.710252] [drm] GPU HANG: ecode 6:0:0x87e8fffd, in MediaPl~ack #23 [5728], reason: Ring hung, action: reset
[22555.712288] drm/i915: Resetting chip after gpu hang
[22892.044206] [drm] stuck on render ring
[22892.045285] [drm] GPU HANG: ecode 6:0:0x87e8fffd, in MediaPl~back #1 [9453], reason: Ring hung, action: reset
[22892.047296] drm/i915: Resetting chip after gpu hang
[23321.489044] [drm] stuck on render ring
[23321.490135] [drm] GPU HANG: ecode 6:0:0x87e8fffd, in MediaPl~back #3 [10156], reason: Ring hung, action: reset
[23321.492075] drm/i915: Resetting chip after gpu hang
[23463.636004] [drm] stuck on render ring
[23463.637070] [drm] GPU HANG: ecode 6:0:0x87e8fffd, in MediaPl~ack #11 [10505], reason: Ring hung, action: reset
[23463.639175] drm/i915: Resetting chip after gpu hang
[27483.794035] [drm] stuck on render ring
[27483.796527] [drm] GPU HANG: ecode 6:0:0x87e8fffd, in MediaPl~back #2 [11839], reason: Ring hung, action: reset
[27483.798767] drm/i915: Resetting chip after gpu hang
[27489.786979] [drm] stuck on render ring
[27489.789461] [drm] GPU HANG: ecode 6:0:0x87e8fffd, in MediaPl~back #6 [11851], reason: Ring hung, action: reset
[27489.789662] [drm:i915_set_reset_status [i915]] *ERROR* gpu hanging too fast, banning!
[27489.791758] drm/i915: Resetting chip after gpu hang

I can reporoduce the bug in Ubuntu 15.10 x86_64. Although I said that the bug had not effect anything, playing HTML5 videos causes freezing, distorted colours in videos. This bug statrs to become annoying. Is there anything I can help?

(In reply to if.gnu.linux from comment #7)
> I can reporoduce the bug in Ubuntu 15.10 x86_64. Although I said that the
> bug had not effect anything, playing HTML5 videos causes freezing, distorted
> colours in videos. This bug statrs to become annoying. Is there anything I
> can help?

We seem to have neglected the bug a bit, apologies.

if.gnu.linux@gmail.com, since there were improvements pushed in kernel, xf86-video-intel & mesa that will benefit to your system, so please re-test with latest kernel, xf86-video-intel & mesa -alternatively you may use modesetting/glamor with latest mesa version- and mark as REOPENED if you can reproduce (and attach fresh kernel log & gpu crash log) and RESOLVED/* if you cannot reproduce.

I can not reproduce the bug so it was fixed.

(In reply to if.gnu.linux from comment #9)
> I can not reproduce the bug so it was fixed.

thanks if.gnu.linux for your confirmation