[Intel-gfx] [PATCH 05/21] drm/i915: Check eDP power when doing aux channel communications

[Chris Wilson]

On Fri, 30 Sep 2011 11:01:06 -0700, Keith Packard <keithp at keithp.com> wrote:
Non-text part: multipart/signed
> On Fri, 30 Sep 2011 19:02:42 +0200, Daniel Vetter <daniel at ffwll.ch> wrote:
> 
> > Use pp_control instead of re-reading?
> 
> Could, but you'll note a later patch eliminates both pp_status and
> pp_control local variables, so I didn't bother to clean this up when
> refactoring.
> 
> > dp_aux_ch does the low-level io for the below, so either this one or the
> > below three hunks look a bit redundant.
> 
> Yeah, probably not necessary. I just added checks everywhere I could
> think of to try and figure out where power was not being applied when
> needed.
> 
> Should I bother to include this patch in the series at all? It's purely
> for diagnostics to make sure the panel is powered during all aux channel
> transactions.

Yes, adding the extra checks made my day. :)

Modesetting bugs are the hardest to reproduce so every additional check
(with a reasonable false positive rate) is worth their weight in gold when
it comes to diagnosing misbehaving hardware. And the checks improve the
maintainability of the code.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre