drm/i915/dp: Be paranoid in case we disable a DP before it is attached
authorChris Wilson <chris@chris-wilson.co.uk>
Sun, 17 Apr 2011 05:38:35 +0000 (06:38 +0100)
committerKeith Packard <keithp@keithp.com>
Wed, 4 May 2011 19:38:02 +0000 (12:38 -0700)
commit31acbcc408f412d1ba73765b846c38642be553c3
tree6a1f340e21b0c24d067eccbc369c1d96098e6ffc
parent2dd251f0a294300a1cf8f4b63768145fa6153c4d
drm/i915/dp: Be paranoid in case we disable a DP before it is attached

Given that the hardware may be left in a random condition by the BIOS,
it is conceivable that we then attempt to clear the DP_PIPEB_SELECT bit
without us ever enabling/attaching the DP encoder to a pipe. Thus
causing a NULL deference when we attempt to wait for a vblank on that
crtc.

Reported-and-tested-by: Bryan Christ <bryan.christ@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=36314
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=36456
Reported-and-tested-by: Bo Wang <bo.b.wang@intel.com>
Cc: stable@kernel.org
Signed-off-by: Keith Packard <keithp@keithp.com>
drivers/gpu/drm/i915/intel_dp.c