System Environment:       
Platform: BSW
Kernel:   v3.19
Mesa:    (10.5)3592cbb21f7b191df5de2d52c7158f93ac284d81
Xf86_video_intel:  (master)2.99.917-156-g1ae0dc460d3a6b0aed763ab4f8f8af02d2af1940
Libdrm: (master)libdrm-2.4.59-23-g1f73578df32f895a678a41758f6c563f49484347
Libva:  (master)f9741725839ea144e9a6a1827f74503ee39946c3
Cairo:  (master)70cc8f250b5669e757b4f044571ba0f71e3dea9e
Xserver: (server-1.16-branch)xorg-server-1.16.4

Bug detailed description:
--------------------------------------------------
GPU hang when run Dota2 games on BSW, it does not exist on BDW.
please the error_state Xorg dmesg glxinfo error info.

Error info:

[ 4644.611649] [drm:valleyview_pipestat_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[ 4902.925128] [drm] stuck on render ring
[ 4902.949551] [drm] GPU HANG: ecode 8:0:0x84df3c04, in dota_linux [6347], reason: Ring hung, action: reset
[ 4902.949559] [drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
[ 4902.949563] [drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
[ 4902.949566] [drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
[ 4902.949569] [drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.
[ 4902.949572] [drm] GPU crash dump saved to /sys/class/drm/card0/error
[ 4902.952036] drm/i915: Resetting chip after gpu hang
[ 4908.921386] [drm] stuck on render ring
[ 4908.946845] [drm] GPU HANG: ecode 8:0:0x84df7c04, in dota_linux [6347], reason: Ring hung, action: reset
[ 4908.948285] drm/i915: Resetting chip after gpu hang
[ 4909.756634] Core dump to |/usr/share/apport/apport 6347 11 0 pipe failed
[ 5284.929772] [drm] stuck on render ring
[ 5284.956681] [drm] GPU HANG: ecode 8:0:0x85df3c1b, in dota_linux [6405], reason: Ring hung, action: reset
[ 5284.958666] drm/i915: Resetting chip after gpu hang
[ 5292.938164] [drm] stuck on render ring
[ 5292.962748] [drm] GPU HANG: ecode 8:0:0x87953c01, in dota_linux [6405], reason: Ring hung, action: reset
[ 5292.965001] drm/i915: Resetting chip after gpu hang
[ 5294.325896] Core dump to |/usr/share/apport/apport 6405 11 0 pipe failed

Reproduce steps:
----------------------------
1, xinit& gnome-session
2, steam
3, Start "Dota2"
4, Click "Play"
5, Choose "training"
6, Click "Start"
7, GPU hang