[Intel-gfx] [PATCH] drm/i915/bdw: MU_FLUSH_DW a qword instead of dword

Damien Lespiau damien.lespiau at intel.com
Thu Mar 6 00:13:26 CET 2014


On Wed, Mar 05, 2014 at 02:38:50PM -0800, Ben Widawsky wrote:
> It wasn't completely fortuitous, I did check. I was lucky you think my
> check was satisfactory though. I agree it makes future code somewhat
> risky so maybe some improvement is needed to safeguard. I also have/had
> a patch to lengthen MI_STORE_DATA_INDEX. The decoder however does not
> complain about that one, and the windows team did neither. So I didn't
> want to change it for the sake of change.

Note that the decoder warns here because the shorter length is not valid
if you believe what's in the spec. It could actually work ok if the CS
hardware respects the length field, don't go fetch the missing dword,
and, as we're not using it, doesn't care too much (which seems to be the
case as we correctly jump to the next instruction). But not quite sure
how well defined this is.

-- 
Damien



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