[Intel-gfx] [PATCH] drm/i915: Pad ringbuffer with NOOPs before wrapping

[Jesse Barnes]

On Sat,  5 Sep 2009 18:07:06 +0100
Chris Wilson <chris at chris-wilson.co.uk> wrote:

> According to the docs, the ringbuffer is not allowed to wrap in the
> middle of an instruction.
> 
> G45 PRM, Vol 1b, p101:
>   While the “free space” wrap may allow commands to be wrapped around
> the end of the Ring Buffer, the wrap should only occur between
> commands. Padding (with NOP) may be required to follow this
> restriction.
> 
> Do as commanded.
> 
> [Having seen bug reports where there is evidence of split commands,
> but apparently the GPU has continued on merrily before a bizarre and
> untimely death, this may or may not fix a few random hangs.]
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> CC: Eric Anholt <eric at anholt.net>

Another potential stable at kernel.org fix?

-- 
Jesse Barnes, Intel Open Source Technology Center