From 39e78234b0be7ae543db8c8ea3cd2e433b8a7bec Mon Sep 17 00:00:00 2001 From: Mika Kuoppala Date: Thu, 7 Jun 2018 20:24:44 +0300 Subject: drm/i915: Add WaKBLVECSSemaphoreWaitPoll There is a problem with kbl up to rev E0 where a heavy memory/fabric traffic from adjacent engine(s) can cause an engine reset to fail. This traffic can be from normal memory accesses or it can be from heavy polling on a semaphore wait. For engine hogging causing a fail, we already fallback to full reset. Which effectively stops all engines and thus we only add a workaround documentation. For the semaphore wait loop poll case, we add one microsecond poll interval to semaphore wait to guarantee bandwidth for the reset preration. The side effect is that we make semaphore completion latencies also 1us longer. v2: Let full reset handle the adjacent engine idling (Chris) v3: Skip render engine (Joonas), please checkpatch on define (Mika) References: https://bugs.freedesktop.org/show_bug.cgi?id=106684 References: VTHSD#2227190, HSDES#1604216706, BSID#0917 Cc: Joonas Lahtinen Cc: Chris Wilson Signed-off-by: Mika Kuoppala Acked-by: Chris Wilson Reviewed-by: Joonas Lahtinen Link: https://patchwork.freedesktop.org/patch/msgid/20180607172444.17080-1-mika.kuoppala@linux.intel.com --- drivers/gpu/drm/i915/intel_uncore.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/gpu/drm/i915/intel_uncore.c') diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c index bb03f6d8b3d1..b892ca8396e8 100644 --- a/drivers/gpu/drm/i915/intel_uncore.c +++ b/drivers/gpu/drm/i915/intel_uncore.c @@ -2174,6 +2174,8 @@ int intel_gpu_reset(struct drm_i915_private *dev_priv, unsigned engine_mask) * Thus assume it is best to stop engines on all gens * where we have a gpu reset. * + * WaKBLVECSSemaphoreWaitPoll:kbl (on ALL_ENGINES) + * * WaMediaResetMainRingCleanup:ctg,elk (presumably) * * FIXME: Wa for more modern gens needs to be validated -- cgit v1.2.3