[Intel-gfx] [PATCH 08/11] drm/intel: add enable_psr module option and disable psr by default

[Daniel Vetter]

On Mon, Jul 15, 2013 at 11:01:13PM +0100, Chris Wilson wrote:
> On Mon, Jul 15, 2013 at 05:23:35PM -0300, Rodrigo Vivi wrote:
> > On Mon, Jul 15, 2013 at 11:01 AM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> > > On Thu, Jul 11, 2013 at 06:45:02PM -0300, Rodrigo Vivi wrote:
> > >> v2: prefer seq_puts to seq_printf detected by Paulo Zanoni.
> > >> v3: PSR is disabled by default. Without userspace ready it
> > >>     will cause regression for kde and xdm users
> > >
> > > I think we should still aim to enable by default and disable on the
> > > first direct access after a mmioflip.
> > 
> > unfortunately I couldn't implement a reliable way of detect it without
> > false positives,
> 
> Can you give me an example of one of the false positives? The detect
> front buffer writes patches we had should be good enough to only punish
> legacy userspace.
> 
> > so let's put this disabled for now and revert when I find a reliable way.
> 
> That's fine, just think we're giving up too easily ;-)

Agreed, and part of the problem is that slacker-me is sitting on a big
review of your rfc patches ;-) I really need to get around to write that
down into a nice mail from my ineligible notes ...

I hope that with good sw side frontbuffer rendering tracking we'll be able
to enable psr in more conditions, e.g. also when sprites are enabled and
similar cases.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch