[Intel-gfx] [PATCH 1/2] drm/i915: Read timings from the correct transcoder in intel_crtc_mode_get()

[Chris Wilson]

Quoting ville.syrjala at linux.intel.com (2016-04-01 16:37:25)
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> intel_crtc->config->cpu_transcoder isn't yet filled out when
> intel_crtc_mode_get() gets called during output probing, so we should
> not use it there. Instead intel_crtc_mode_get() figures out the correct
> transcoder on its own, and that's what we should use.
> 
> If the BIOS boots LVDS on pipe B, intel_crtc_mode_get() would actually
> end up reading the timings from pipe A instead (since PIPE_A==0),
> which clearly isn't what we want.
> 
> It looks to me like this may have been broken by
> commit eccb140bca67 ("drm/i915: hw state readout&check support for cpu_transcoder")
> as that one removed the early initialization of cpu_transcoder from
> intel_crtc_init().
> 
> Cc: stable at vger.kernel.org
> Cc: dri-devel at lists.freedesktop.org
> Cc: Rob Kramer <rob at solution-space.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Reported-by: Rob Kramer <rob at solution-space.com>
> Fixes: eccb140bca67 ("drm/i915: hw state readout&check support for cpu_transcoder")
> References: https://lists.freedesktop.org/archives/dri-devel/2016-April/104142.html
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Matches the writing on the tin.
The effect is to s/intel_crtc->config->cpu_transcoder/intel_crtc->pipe/
and aiui, the dvo path will call this before
intel_crtc->config->cpu_transcoder is ever set.

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris