[Mesa-dev] [PATCH 2/3] intel: Do temporary CPU maps of textures that are too big to GTT map.

[Eric Anholt]

Daniel Vetter <daniel at ffwll.ch> writes:

> On Tue, Apr 02, 2013 at 06:46:32PM -0700, Eric Anholt wrote:
>> This still fails, since 8192*4bpp == 32768, which is too big to use the
>> blitter on.
>
> Meh, I should take coffee first before doing reviews ...
>
> Iirc on gen4+ for tiled src/dst the blt stride limit is 128k (since the
> stride is supplied in dwords instead of bytes).

Good point, I could be more look just at the pitch that we would make
for the temporary BO, except that our interface for calling the blitter
is uint16_t bytes, so 128k would fail anyway.  Something to fix later
imo.

> Also, with the new
> snoopable bo support in the kernel v3.7 you should be able to use the
> blitter also on non-llc platforms (safe for i965g/gm, the hw is busted
> there), which will cut away the clflushing when accessing the cpu maps.
> -Daniel

Yeah, we'd need to get that hooked up correctly in libdrm so that
non-llc snoopable BOs don't get returned to the BO cache.
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