Re: [PATCH 2/2] drm/i915: use semaphores for the display plane

[Ben Widawsky <ben@bwidawsk.net>]

On Thu, 22 Mar 2012 16:18:54 +0000
Chris Wilson <chris@chris-wilson.co.uk> wrote:

> On Thu, 22 Mar 2012 09:07:09 -0700, Ben Widawsky <ben@bwidawsk.net> wrote:
> > On Thu, 22 Mar 2012 09:56:07 +0000
> > Chris Wilson <chris@chris-wilson.co.uk> wrote:
> > 
> > > On Wed, 21 Mar 2012 17:19:13 -0700, Ben Widawsky <ben@bwidawsk.net>
> > > wrote:
> > > >   * For the display plane, we want to be in the GTT but out of any
> > > > write
> > > > - * domains. So in many ways this looks like set_to_gtt_domain()
> > > > apart from the
> > > > - * ability to pipeline the waits, pinning and any additional
> > > > subtleties
> > > > - * that may differentiate the display plane from ordinary buffers.
> > > > + * domains. So in many ways this looks like set_to_gtt_domain().
> > > ...apart from the whole pinning and pipelining. It looks less like
> > > set-to-gtt-domain over time.
> > > 
> > > Not an improvement. I'll be the first to admit that it is not a great
> > > comment, but at least it does try to capture why we don't just treat
> > > the display plane as GTT. A better comment would explain our concept
> > > of display plane and pipelining.
> > 
> > Separate patch though, don't you think? And it is now pipe-lining the
> > waits, so I'm confused why you don't think it's an improvement.
> 
> Right. So how does removing the hint of why pin-to-display is different
> from set-to-gtt when it now performs said function help improve the
> comment? I completely agree that changing that comment is outside of the
> scope of this patch.
> -Chris
> 

Can you volunteer a better description? I'll undo the comment change in
my patch #2 and use whatever you come up with. If not, I'll get to this
when I get to it.