[Intel-gfx] [PATCH 09/12] Do more checks for proposed flip pixmaps

Ville Syrjälä ville.syrjala at linux.intel.com
Thu Jul 31 09:06:50 PDT 2014

On Thu, Jul 31, 2014 at 08:20:20AM -0700, Keith Packard wrote:
> Ville Syrjälä <ville.syrjala at linux.intel.com> writes:
> > Now that we have mmio flips in the kernel we can start to relax that
> > restriction. That still needs a bit more work in the mmio flip code
> > but I believe some people working on just that.
> I couldn't find any tiling restrictions in the current (ring-based) flip
> code; did I just miss them?

No, changing tiling is supposed to work via cs flips. Except it
doesn't actually work on VLV for some reason. We now fall back to
mmio flip on VLV for that, so given a recent enough kernel it should
just work (tm) on all platforms.

I was referring to the relaxing the restrictions on stride changes.

> > We could even change the pixel format, except a check was added to
> > drm_mode_page_flip_ioctl() to prevent that, so I guess it was
> > deemed that the API isn't meant to allow that.
> Yeah, not sure I care about this; 32bpp is pretty much the only format I
> want.

You just need to be careful with the X vs. A because the kernel
considers those distinct pixel formats. I now regret adding that
distinciton to the pixel formats, but sadly I don't own a time
machine so I can't undo it.

Ville Syrjälä
Intel OTC

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