[Intel-gfx] [PATCH 4/5] drm/i915: add some assertions about VBT DDI port types

[Chris Wilson]

On Wed, Sep 11, 2013 at 06:02:50PM -0300, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
> 
> Our code makes a lot of assumptions regarding what each DDI port
> actually supports, and the VBT should tell us what is really happening
> in the hardware. So parse the information provided by the VBT and
> check if any of our assumptions is wrong.
> 
> Our driver also has a history of not really trusting the VBT, so a
> WARN here could mean that:
>  a) our coding assumptions are wrong
>  b) the VBT is wrong
>  c) we're incorrectly parsing the VBT
>  d) the checks are wrong
> 
> But I really hope we won't ever trigger any of those WARNs.
> 
> v2: Don't check the redundant "Capabilities" field from byte 24 since
>     it doesn't seem to be used.
> v3: Rebase
> 
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> Reviewed-by: Rodrigo Vivi <rodrigo.vivi at gmail.com> (v2)

I have the same issue with these WARN - single callsite, no need for
disambiguation, and things we need to handle rather than bamboozle the
user. (Or if we can't, *ERROR* when it all goes wrong.)
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre