[Intel-gfx] [PATCH] drm/i915 : Removed the unconditional cross engine/ring update of MBOX registers

[Chris Wilson]

On Tue, Jun 10, 2014 at 12:48:44PM +0530, sourab.gupta at intel.com wrote:
> From: Akash Goel <akash.goel at intel.com>
> 
> Removed the unconditional cross engine/ring update of MBOX registers.
> The MBox update will done only when needed when the actual inter ring
> dependency has been ascertained. Although this late sync could affect
> the Media performance slightly but it shall improve the residency time
> of individual power wells in C6 state.

NAK. Did you even consider the deadlocks above and beyond the issues with
latency? Maybe suggest that the hardware guys consider a reordering write
FIFO next time like elsewhere on the chip.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre