From: Daniel Vetter Date: Tue, 27 Mar 2012 07:31:24 +0000 (+0200) Subject: drm/i915: apply CS reg readback trick against missed IRQ on snb X-Git-Tag: MMI-PSA29.97-13-9~17070^2^2~7 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=1c7eaac737e4cca24703531ebcb566afc3ed285f;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git drm/i915: apply CS reg readback trick against missed IRQ on snb Ben Widawsky reported missed IRQ issues and this patch here helps. We have one other missed IRQ report still left on snb, reported by QA: https://bugs.freedesktop.org/show_bug.cgi?id=46145 This is _not_ a regression due to the forcewake voodoo though, it started showing up before that was applied and has been on-and-off for the past few weeks. According to QA this patch does not help. But the missed IRQ is always from the blt ring (despite running piglit, so also render activity expected), so I'm hopefully that this is an issue with the blt ring itself. Tested-by: Ben Widawsky Signed-Off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index fc66af6a9448..e25581a9f60f 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -626,7 +626,7 @@ gen6_ring_get_seqno(struct intel_ring_buffer *ring) /* Workaround to force correct ordering between irq and seqno writes on * ivb (and maybe also on snb) by reading from a CS register (like * ACTHD) before reading the status page. */ - if (IS_GEN7(dev)) + if (IS_GEN6(dev) || IS_GEN7(dev)) intel_ring_get_active_head(ring); return intel_read_status_page(ring, I915_GEM_HWS_INDEX); }