[Intel-gfx] [PATCH 3/3] drm/i915: use the gmbus irq for waits

[Chris Wilson]

On Wed,  5 Sep 2012 21:24:41 +0200, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> We need two special things to properly wire this up:
> - Add another argument to gmbus_wait_hw_status to pass in the
>   correct interrupt bit in gmbus4.
> - Since we can only get an irq for one of the two events we want,
>   hand-roll the wait_event_timeout code so that we wake up every
>   jiffie and can check for NAKs. This way we also subsume gmbus
>   support for platforms without interrupts (or where those are not
>   yet enabled).
> 
> The important bit really is to only enable one gmbus interrupt source
> at the same time - with that piece of lore figured out, this seems to
> work flawlessly.

Outline looks good. Did have a worry over the conversion to schedule(1),
but then realised that is equivalent to the current msleep. So there is
a potential that we need to do better for gen2/3.

Need to dig a little more, so just a-b for now.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre