drm/i915: Wait for vblank before enabling the TV encoder
The vblank waits in intel_tv_detect_type() are timing out for some reason. This is a regression caused removing seemingly useless vblank waits from the modeset seqeuence in: commit 56ef52ca Author: Ville Syrjälä <ville.syrjala@linux.intel.com> Date: Thu May 8 19:23:15 2014 +0300 drm/i915: Kill vblank waits after pipe enable on gmch platforms So it turns out they weren't all entirely useless. Apparently the pipe has to go through one full frame before we enable the TV port. Add a vblank wait to intel_enable_tv() to make sure that happens. Another approach was attempted by placing the vblank wait just after enabling the port. The theory behind that attempt was that we need to let the port stay enabled for one full frame before disabling it again during load detection. But that didn't work, and we definitely must have the vblank wait before enabling the port. Cc: stable@vger.kernel.org Cc: Alan Bartlett <ajb@elrepo.org> Tested-by: Alan Bartlett <ajb@elrepo.org> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=79311Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
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