From 274de876065a34ca1ff093bfacb62e440a4491be Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 2 Feb 2018 14:54:55 +0000 Subject: [PATCH] drm/i915/execlists: Flush GTIIR on clearing CS interrupts during reset Be paranoid and flush the GTIIR after clearing the CS interrupt to be sure it has taken before we re-enable the interrupt handler. We still see early interrupts following reset, the tasklet handling the mmio read before it has been written by the CS. This hopefully reduces the frequency to 0... References: https://bugs.freedesktop.org/show_bug.cgi?id=104262 Signed-off-by: Chris Wilson Cc: Mika Kuoppala Cc: Michel Thierry Cc: Tvrtko Ursulin Acked-by: Michel Thierry Link: https://patchwork.freedesktop.org/patch/msgid/20180202145455.29876-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/intel_lrc.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index 40dbeaee9dfa..deeedfc9fe44 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -1527,6 +1527,7 @@ static int gen9_init_render_ring(struct intel_engine_cs *engine) static void reset_irq(struct intel_engine_cs *engine) { struct drm_i915_private *dev_priv = engine->i915; + int i; /* * Clear any pending interrupt state. @@ -1535,10 +1536,14 @@ static void reset_irq(struct intel_engine_cs *engine) * buffered, and if we only reset it once there may still be * an interrupt pending. */ - I915_WRITE(GEN8_GT_IIR(gtiir[engine->id]), - GT_CONTEXT_SWITCH_INTERRUPT << engine->irq_shift); - I915_WRITE(GEN8_GT_IIR(gtiir[engine->id]), - GT_CONTEXT_SWITCH_INTERRUPT << engine->irq_shift); + for (i = 0; i < 2; i++) { + I915_WRITE(GEN8_GT_IIR(gtiir[engine->id]), + GT_CONTEXT_SWITCH_INTERRUPT << engine->irq_shift); + POSTING_READ(GEN8_GT_IIR(gtiir[engine->id])); + } + GEM_BUG_ON(I915_READ(GEN8_GT_IIR(gtiir[engine->id])) & + (GT_CONTEXT_SWITCH_INTERRUPT << engine->irq_shift)); + clear_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted); } -- 2.30.2