On 17/11/2016 09:28, Chris Wilson wrote:
On Thu, Nov 17, 2016 at 09:17:35AM +0000, Tvrtko Ursulin wrote:From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> Commit ed4596ea992d ("drm/i915/guc: WA to address the Ringbuffer coherency issue"), based on incorrect assumptions from a partialy broken commit 0dd356bb6ff5 ("drm/i915: Eliminate Gen9 special case") used POSTING_READ_FW instead of the POSTING_READ. With the latter buggy commit fixed this call site needs fixing as well.The theory here is that we don't need the powerwell to force the write from CPU to be visible before another agent. I missed the report, so I am genuinely interested in knowing whether the theory about the write being posted without the powerwll.
Just that the commit message for the patch used "guc registers are not in any forcewake domain" reasoning, which was false - based on a partially broken patch. See "drm/i915: Fix gen9 forcewake range table".
Regards, Tvrtko _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
