[Intel-gfx] [PATCH] drm/i915: preserve pipe A quirk in i9xx_set_pipeconf

[Chris Wilson]

On Mon, Sep 23, 2013 at 10:37:02AM +0200, Daniel Vetter wrote:
> On Mon, Sep 23, 2013 at 10:17 AM, Ville Syrjälä
> <ville.syrjala at linux.intel.com> wrote:
> > Hmm. Why not just this?
> >
> > pipeconf = 0;
> > if (pipe == PIPE_A && QUIRK)
> >  pipeconf |= PIPECONF_ENABLE;
> 
> After resume the bios might or might not have enabled pipe A already.
> We have a bit of magic to make sure that on resume we set up a decent
> mode for pipe A, but I fear if I just smash pipe A to always on we'd
> enable it in a bogus state and hang the hw. Hence the readback.

Yet, the

if (A)
  pipeconf = READ() & MAGIC;
else
  pipeconf = 0;
if (B)
  pipeconf = READ() & MAGIC2;

is still ugly.

Good news, testing nightly+ with patch results in machine death. Now
seeing just where death creeps in.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre