Created attachment 97047 [details]
content of /sys/class/drm/card0/error

Got sudden hang of all video, self restored after few seconds.

dmesg:
[47188.297987] [drm] stuck on render ring
[47188.297996] [drm] stuck on blitter ring
[47188.297998] [drm] GPU crash dump saved to /sys/class/drm/card0/error
[47188.297999] [drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
[47188.298000] [drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
[47188.298001] [drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
[47188.298002] [drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.

content of /sys/class/drm/card0/error in attachement.

System Information
	Manufacturer: LENOVO
	Product Name: 4298R86
	Version: ThinkPad X220 Tablet
	Serial Number: R9MN226
	UUID: 92958D81-525A-11CB-A156-A2101B6842BF
	Wake-up Type: Power Switch
	SKU Number: Not Specified
	Family: ThinkPad X220 Tablet
Base Board Information
	Manufacturer: LENOVO
	Product Name: 4298R86
	Version: Not Available
	Serial Number: 1ZKZW22M4Y8
	Asset Tag: Not Available

lcpci:

00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09) (prog-if 00 [VGA controller])
	Subsystem: Lenovo Device 21db
	Flags: bus master, fast devsel, latency 0, IRQ 42
	Memory at f0000000 (64-bit, non-prefetchable) [size=4M]
	Memory at e0000000 (64-bit, prefetchable) [size=256M]
	I/O ports at 4000 [size=64]
	Expansion ROM at <unassigned> [disabled]
	Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
	Capabilities: [d0] Power Management version 2
	Capabilities: [a4] PCI Advanced Features
	Kernel driver in use: i915

Ubuntu 14.04, stock kernel.

uname -a
Linux x220 3.13.0-21-generic #43-Ubuntu SMP Mon Mar 31 22:56:15 UTC 2014 i686 i686 i686 GNU/Linux

boot options:
BOOT_IMAGE=/boot/vmlinuz-3.13.0-21-generic root=UUID=3d4ce850-6e8a-4cf5-9b82-fb135c22fe1e ro i915_enable_rc6=1 pcie_aspm=force i915.semaphores=1

ii  xserver-xorg-video-intel                              2:2.99.910-0ubuntu1                    i386         X.Org X server -- Intel i8xx, i9xx display driver
ii  xorg                                                  1:7.7+1ubuntu8                         i386         X.Org X Window System

X log:
(EE) [mi] EQ overflowing.  Additional events will be discarded until existing events are processed.
(EE)
(EE) Backtrace:
(EE) 0: /usr/bin/X (xorg_backtrace+0x4f) [0xb76ccb0f]
(EE) 1: /usr/bin/X (mieqEnqueue+0x213) [0xb76acc53]
(EE) 2: /usr/bin/X (QueuePointerEvents+0x6d) [0xb757a2ad]
(EE) 3: /usr/bin/X (xf86PostMotionEventM+0x24b) [0xb75b398b]
(EE) 4: /usr/lib/xorg/modules/input/evdev_drv.so (0xb6496000+0x498f) [0xb649a98f]
(EE) 5: /usr/bin/X (0xb7525000+0x7dff5) [0xb75a2ff5]
(EE) 6: /usr/bin/X (0xb7525000+0xa8c0b) [0xb75cdc0b]
(EE) 7: (vdso) (__kernel_sigreturn+0x0) [0xb7502400]
(EE) 8: (vdso) (__kernel_vsyscall+0x10) [0xb7502424]
(EE) 9: /lib/i386-linux-gnu/libc.so.6 (ioctl+0x19) [0xb71ca899]
(EE) 10: /usr/lib/i386-linux-gnu/libdrm.so.2 (drmIoctl+0x40) [0xb73eea00]
(EE) 11: /usr/lib/i386-linux-gnu/libdrm_intel.so.1 (0xb6aa5000+0x5eac) [0xb6aaaeac]
(EE) 12: /usr/lib/i386-linux-gnu/libdrm_intel.so.1 (drm_intel_bo_subdata+0x28) [0xb6aa72c8]
(EE) 13: /usr/lib/xorg/modules/drivers/intel_drv.so (0xb6ac7000+0x11147a) [0xb6bd847a]
(EE) 14: /usr/lib/xorg/modules/drivers/intel_drv.so (0xb6ac7000+0x11779d) [0xb6bde79d]
(EE) 15: /usr/lib/xorg/modules/drivers/intel_drv.so (0xb6ac7000+0x12882b) [0xb6bef82b]
(EE) 16: /usr/lib/xorg/modules/drivers/intel_drv.so (0xb6ac7000+0xd103) [0xb6ad4103]
(EE) 17: /usr/lib/xorg/modules/drivers/intel_drv.so (0xb6ac7000+0x131e42) [0xb6bf8e42]
(EE) 18: /usr/bin/X (0xb7525000+0x12911e) [0xb764e11e]
(EE) 19: /usr/bin/X (CompositePicture+0x298) [0xb763f058]
(EE) 20: /usr/lib/xorg/modules/drivers/intel_drv.so (0xb6ac7000+0x133277) [0xb6bfa277]
(EE) 21: /usr/bin/X (CompositeTrapezoids+0x9e) [0xb763f2ee]
(EE) 22: /usr/bin/X (0xb7525000+0x11f3fb) [0xb76443fb]
(EE) 23: /usr/bin/X (0xb7525000+0x11a74d) [0xb763f74d]
(EE) 24: /usr/bin/X (0xb7525000+0x3cbdd) [0xb7561bdd]
(EE) 25: /usr/bin/X (0xb7525000+0x40d05) [0xb7565d05]
(EE) 26: /usr/bin/X (0xb7525000+0x2aaae) [0xb754faae]
(EE) 27: /lib/i386-linux-gnu/libc.so.6 (__libc_start_main+0xf3) [0xb7100a83]
(EE) 28: /usr/bin/X (0xb7525000+0x2aae4) [0xb754fae4]
(EE)


xrandr config:
xrandr 
Screen 0: minimum 320 x 200, current 4480 x 1440, maximum 8192 x 8192
LVDS1 connected (normal left inverted right x axis y axis)
   1366x768       60.0 +
   1360x768       59.8     60.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
VGA1 connected 1920x1200+2560+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200      60.0*+
   1920x1080      60.0  
   1600x1200      60.0  
   1680x1050      60.0  
   1280x1024      60.0  
   1280x960       60.0  
   1024x768       60.0  
   800x600        60.3  
   640x480        60.0  
   720x400        70.1  
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 connected 2560x1440+0+0 (normal left inverted right x axis y axis) 597mm x 336mm
   2560x1440      60.0*+
   1920x1200      59.9  
   1920x1080      60.0     60.0     50.0     59.9     24.0     24.0  
   1920x1080i     60.1     50.0     60.0  
   1600x1200      60.0  
   1680x1050      60.0  
   1280x1024      75.0     60.0  
   1280x800       59.8  
   1152x864       75.0  
   1280x720       60.0     50.0     59.9  
   1024x768       75.1     60.0  
   800x600        75.0     60.3  
   720x576        50.0  
   720x480        60.0     59.9  
   640x480        75.0     60.0     59.9  
   720x400        70.1  


active application: 3D game, eternallands, xfce desktop environment, game was on VGA1 output during hang.