[Intel-gfx] [PATCH 3/5] drm/i915: check the DDC and AUX bits of the VBT on DDI machines

[Chris Wilson]

On Wed, Sep 11, 2013 at 06:02:49PM -0300, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
> 
> Our code currently assumes that port X will use the DP AUX channel X
> and the DDC pin X. The VBT should tell us how things are mapped, so
> add some WARNs in case we discover our assumptions are wrong (or in
> case the VBT is just wrong, which is also perfectly possible).
> 
> Why would someone wire port B to AUX C and DDC D?
> 
> v2: Rebase

A WARN isn't going to be very helpful, these calls can only occur in a
single callpath, so there is is no confusion. Also it is not *ERROR*
worthy if the VBT is broken, we just get to pick up the pieces.

These are only DEBUG class warnings. If you want to get fancy, you can
put a "told you so" *ERROR* after it doesn't work.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre