[Mesa-dev] [PATCH] i965: Disable compaction for EOT send messages

[Matt Turner]

On Wed, May 27, 2015 at 10:16 PM, Ben Widawsky
<benjamin.widawsky at intel.com> wrote:
> AFAICT, there is no real way to make sure a send message with EOT is properly
> ignored from compact, nor can I see a way to actually encode EOT while
> compacting. Before the single send optimization we'd always bail because we hit
> the is_immediate && !is_compactable_immediate case. However, with single send,
> is_immediate is not true, and so we end up trying to compact the un-compactible.
>
> Without this, any compacting single send instruction will hang because the EOT
> isn't there. I am not sure how I didn't hit this when I originally enabled the
> optimization.  I didn't check if some surrounding code changed.
>
> NOTE: This needs another piglit run or two before merge.
>
> I know Neil and Matt were both looking into this. I did a quick search and
> didn't see any patches out there to handle this. Please ignore if this has
> already been sent by someone. (Direct me to it and I will review it).
>
> Cc: Matt Turner <mattst88 at gmail.com>
> Cc: Neil Roberts <neil at linux.intel.com>
> Cc: Mark Janes <mark.a.janes at intel.com>
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>

I haven't figured out precisely how EOT's getting lost yet, but Mark
says that with this patch we can actually complete a piglit run, so
let's do it.

Reviewed-by: Matt Turner <mattst88 at gmail.com>