Created attachment 98534 [details]
dmesg

*System Environment:
--------------------------
Regression: Yes. 
Reset igt to 5188bbe23ea6e7a2bf4d5572b64f410399aba9f7, the error was same with bug 71333 

Non-working platforms: All
Working platforms: No

 *kernel: 
--------------------------
-nightly: 08ce6614d07dd1e426109672a5e323317c8d6ec7 (fails)
-queued: e5c03ca362819ba8ffbe5674340b61b9cd75de8f (fails)
    Author: Daniel Vetter <daniel.vetter@ffwll.ch>
    Date:   Thu Apr 24 23:54:45 2014 +0200

    drm/i915/sdvo: Remove ->mode_set callback

    SDVO is used by both crtcs using the i9xx_ and the ironlake_
    functions. For both cases there is nothing between the
    encoder->mode_set and the encoder->pre_enable calls that touches the
    hardware.

    The vlv_ functions are different since they enable the pll before the
    ->pre_enable hook. But SDVO isn't supported on vlv platforms, so this
    doesn't matter.

    We've also already clean up all the sdvo state computation logic, all
    relevant parts are already in the ->compute_config hook.  So we can
    just get rid of the ->mode_set hook by converting it to a ->pre_enable
    hook.

    Reviewed-by: Imre Deak <imre.deak@intel.com>
    Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

-fixes: 9bbfd20abe5025adbb0ac75160bd2e41158a9e83 (fails)
    Author: Paulo Zanoni <paulo.r.zanoni@intel.com>
    Date:   Tue Apr 29 11:00:22 2014 -0300

    drm/i915: don't try DP_LINK_BW_5_4 on HSW ULX

    Because the docs say ULX doesn't support it on HSW.

    Reviewed-by: Dave Airlie <airlied@redhat.com>
    Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
    Signed-off-by: Jani Nikula <jani.nikula@intel.com>

 *Bug detailed description:
-----------------------------
igt/drv_hangman fails

Output:
 ./drv_hangman
checking /sys/kernel/debug/dri/0/i915_error_state
rings stopped
Warning on condition flags != 0 in fucntion check_stop_rings, file drmtest.c:97
i915_ring_stop flags on exit 0xf, can't quiescent gpu cleanly
gpu hang not detected

if reset igt to 5188bbe23ea6e7a2bf4d5572b64f410399aba9f7, then run the test, the output was:
 ./drv_hangman
checking /sys/kernel/debug/dri/0/i915_error_state
rings stopped
gpu hang correctly detected
checking /sys/class/drm/card0/error
rings stopped
gpu hang correctly detected


 *Reproduce steps:
---------------------------- 
1. ./drv_hangman