drm/i915: Fix the PPT fdi lane bifurcate state handling on ivb
Originally I've thought that this is leftover hw state dirt from the BIOS. But after way too much helpless flailing around on my part I've noticed that the actual bug is when we change the state of an already active pipe. For example when we change the fdi lines from 2 to 3 without switching off outputs in-between we'll never see the crucial on->off transition in the ->modeset_global_resources hook the current logic relies on. Patch version 2 got this right by instead also checking whether the pipe is indeed active. But that in turn broke things when pipes have been turned off through dpms since the bifurcate enabling is done in the ->crtc_mode_set callback. To address this issues discussed with Ville in the patch review move the setting of the bifurcate bit into the ->crtc_enable hook. That way we won't wreak havoc with this state when userspace puts all other outputs into dpms off state. This also moves us forward with our overall goal to unify the modeset and dpms on paths (which we need to have to allow runtime pm in the dpms off state). Unfortunately this requires us to move the bifurcate helpers around a bit. Also update the commit message, I've misanalyzed the bug rather badly. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=70507 Tested-by:Jan-Michael Brummer <jan.brummer@tabos.org> Cc: stable@vger.kernel.org Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by:
Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by:
Daniel Vetter <daniel.vetter@ffwll.ch>
parent
645378d8
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