Re: [PATCH 4/5] drm/i915: Add async page flip support for IVB

From: Keith Packard
Date: Wed Jul 24 2013 - 16:26:48 EST

Daniel Vetter <daniel@xxxxxxxx> writes:

> Matching tiling modes is actually already a requirement on gen4+ (since
> the tiling bit and the linear/tiled offset registers can't be changed with
> a MI_DISPLAY_FLIP command).

Async flip has a harder requirement -- you must use X tiling, both
before and after the flip. Oh, and async flips require a 32KB aligned
buffer, which I'm not actually checking for. Not sure how to

> But atm we fail to check that in the common
> code, so imo better to move that to there.
> We already check for matching strides in common code, so with the tile
> check added we could drop this all here.

I don't see a requirement for matching stride and tile parameter in the
MI_DISPLAY_FLIP docs for synchronous operations, at least on DevGT+. Is
the common code too restrictive?


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