-
Chris Wilson authored
Broadwell and later currently use the same unordered command sequence to update the seqno in the HWS status page and then assert the user interrupt. We should apply the w/a from legacy (where we do an mmio read to delay the seqno read after the interrupt), but this is not enough to enforce coherent seqno visibilty on Skylake. Rather than search for the proper post-interrupt seqno barrier, use a strongly ordered command sequence to write the seqno, then assert the user interrupt from the ring. v2: Move around the wa tail dwords to avoid adding duplicate code. v3: Add references, comments on workarounds and bit5 check. References: https://bugs.freedesktop.org/show_bug.cgi?id=93693 Testcase: igt/gem_ring_sync_loop #skl Signed-off-by:
Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@intel.com> Reviewed-by:
Mika Kuoppala <mika.kuoppala@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1453297415-17793-1-git-send-email-mika.kuoppala@intel.com
7c17d377