Created attachment 117124 [details]
/sys/class/drm/card0/error

System Environment:
--------------------------
CPU: Intel Core i5 M 460
Distro: Frugalware Linux
kernel-4.0.4
xf86-video-intel-2.99.917
mesa-10.6.2
kde-4.14.3

Watching a video with hw acceleration enabled (vaapi) causes the player to hang once as soon as I do something.
Looking at dmesg here's what it says:

[drm] stuck on render ring
[drm] GPU HANG: ecode 5:0:0x9ffdffff, in mpv/vo [993], reason: Ring hung, action: reset
[drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
[drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
[drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
[drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.
[drm] GPU crash dump saved to /sys/class/drm/card0/error
drm/i915: Resetting chip after gpu hang
[drm] PCIE GART of 1024M enabled (table at 0x000000000025E000).
radeon 0000:01:00.0: WB enabled
radeon 0000:01:00.0: fence driver on ring 0 use gpu addr 0x0000000020000c00 and cpu addr 0xffc58c00
radeon 0000:01:00.0: fence driver on ring 3 use gpu addr 0x0000000020000c0c and cpu addr 0xffc58c0c
radeon 0000:01:00.0: fence driver on ring 5 use gpu addr 0x000000000005c418 and cpu addr 0xf9d1c418
[drm] ring test on 0 succeeded in 1 usecs
[drm] ring test on 3 succeeded in 5 usecs
[drm] ring test on 5 succeeded in 2 usecs
[drm] UVD initialized successfully.
[drm] ib test on ring 0 succeeded in 0 usecs
[drm] ib test on ring 3 succeeded in 0 usecs
[drm] ib test on ring 5 succeeded

I've attached /sys/class/drm/card0/error.
When this happens kwin crashes if desktop effects are enabled.
The player I'm using is mpv --hwdec=vaapi, but same happens with vlc and flashplayer.

The issue has started with mesa-10.6.0, and was still present a few days ago when I tried the latest git revision (anyway I have the issue with 10.6.2),
while everything works fine with mesa-10.5.x

I had a look with git bisect and this is the result (I hope it helps):

0e0e23ef537c9add672ff322f34e129a07edc55e is the first bad commit
commit 0e0e23ef537c9add672ff322f34e129a07edc55e
Author: Jordan Justen <jordan.l.justen@intel.com>
Date:   Wed Apr 22 11:43:50 2015 -0700

    i965/state: Emit pipeline select when changing pipelines
    
    Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
    Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

:040000 040000 725572870b90c40592e3d382faef748469403f67 ae158c5c1fc9c0487dbfad8b338ebdb27300c0a1 M      src



Others (maybe) useful infos follow:

lspci:
00:02.0 VGA compatible controller [0300]: Intel Corporation Core Processor Integrated Graphics Controller [8086:0046] (rev 02) (prog-if 00 [VGA controller])
        Subsystem: Hewlett-Packard Company Device [103c:149c]
        Flags: bus master, fast devsel, latency 0, IRQ 30
        Memory at c0000000 (64-bit, non-prefetchable) [size=4M]
        Memory at b0000000 (64-bit, prefetchable) [size=256M]
        I/O ports at 5050 [size=8]
        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

01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Park [Mobility Radeon HD 5430/5450/5470] [1002:68e0] (prog-if 00 [VGA controller])
        Subsystem: Hewlett-Packard Company Device [103c:149c]
        Flags: bus master, fast devsel, latency 0, IRQ 31
        Memory at a0000000 (64-bit, prefetchable) [size=256M]
        Memory at c4400000 (64-bit, non-prefetchable) [size=128K]
        I/O ports at 4000 [size=256]
        Expansion ROM at c4440000 [disabled] [size=128K]
        Capabilities: [50] Power Management version 3
        Capabilities: [58] Express Legacy Endpoint, MSI 00
        Capabilities: [a0] MSI: Enable+ Count=1/1 Maskable- 64bit+
        Capabilities: [100] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?>
        Kernel driver in use: radeon


vainfo:
libva info: VA-API version 0.38.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/dri/i965_drv_video.so
libva info: Found init function __vaDriverInit_0_37
libva info: va_openDriver() returns 0
vainfo: VA-API version: 0.38 (libva 1.6.0)
vainfo: Driver version: Intel i965 driver for Intel(R) Ironlake Mobile - 1.5.1
vainfo: Supported profile and entrypoints
      VAProfileMPEG2Simple            : VAEntrypointVLD
      VAProfileMPEG2Main              : VAEntrypointVLD
      VAProfileH264ConstrainedBaseline: VAEntrypointVLD
      VAProfileH264Main               : VAEntrypointVLD
      VAProfileH264High               : VAEntrypointVLD
      VAProfileNone                   : VAEntrypointVideoProc


I apologize if mesa isn't the right component, but my only clues was that the issue started after the mesa upgrade;
feel free to move to a more suited section if needed, and tell me if I forgot any useful info.