Xorg Problems upgrading to 4.0

[Francois Tigeot]

On Mon, Dec 15, 2014 at 11:05:29PM -0800, kyuupichan wrote:
>     0   1143      0   1142 111 220   0 163000  51584 lwe      D0L    ??    0:28.20 /usr/local/bin/X :7 -auth /home/neil/.serverauth.1129 (Xorg)
>     0   1143      1   1142   0 152   0 163000  51584 umtxsl   S0L    ??    0:00.00 /usr/local/bin/X :7 -auth /home/neil/.serverauth.1129 (Xorg)

There are two Xorg threads and both appear to be sleeping.

The first one is waiting in a wait_event() call

The drm/radeon driver only uses the wait_event_timeout() and
wait_event_interruptible_timeout() variants so it's unlikely to be the
culprit.

Howewer, the drm/ttm memory manager may use the straight wait_event() variant
without a timeout in the ttm_bo_wait_unreserved() function.

Our ttm_bo_wait_unreserved() function is from Linux 3.9 and I see its
implementation has been changed in more recent Linux versions to not use
wait_event() anymore.

We may have inherited an upstream bug here.

-- 
Francois Tigeot