From f747026c2b350fdb3c2d6fad51b7ebed4851183e Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 24 Jan 2017 15:20:21 +0000 Subject: [PATCH] drm/i915: Only run execlist context-switch handler after an interrupt Mark when we run the execlist tasklet following the interrupt, so we don't probe a potentially uninitialised register when submitting the contexts multiple times before the hardware responds. v2: Use a shared engine->irq_posted v3: Always use locked bitops to be sure of atomicity wrt to other bits in the mask. Signed-off-by: Chris Wilson Cc: Mika Kuoppala Cc: Tvrtko Ursulin Link: http://patchwork.freedesktop.org/patch/msgid/20170124152021.26587-1-chris@chris-wilson.co.uk Reviewed-by: Mika Kuoppala --- drivers/gpu/drm/i915/i915_irq.c | 7 +++++-- drivers/gpu/drm/i915/intel_lrc.c | 3 ++- drivers/gpu/drm/i915/intel_ringbuffer.h | 1 + 3 files changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index 7e087c344265..3f3c9082b0f8 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -1349,8 +1349,11 @@ gen8_cs_irq_handler(struct intel_engine_cs *engine, u32 iir, int test_shift) { if (iir & (GT_RENDER_USER_INTERRUPT << test_shift)) notify_ring(engine); - if (iir & (GT_CONTEXT_SWITCH_INTERRUPT << test_shift)) - tasklet_schedule(&engine->irq_tasklet); + + if (iir & (GT_CONTEXT_SWITCH_INTERRUPT << test_shift)) { + set_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted); + tasklet_hi_schedule(&engine->irq_tasklet); + } } static irqreturn_t gen8_gt_irq_ack(struct drm_i915_private *dev_priv, diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index 9896027880ea..f729568e5e54 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -564,7 +564,7 @@ static void intel_lrc_irq_handler(unsigned long data) intel_uncore_forcewake_get(dev_priv, engine->fw_domains); - if (!execlists_elsp_idle(engine)) { + while (test_and_clear_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted)) { u32 __iomem *csb_mmio = dev_priv->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine)); u32 __iomem *buf = @@ -1297,6 +1297,7 @@ static int gen8_init_common_ring(struct intel_engine_cs *engine) DRM_DEBUG_DRIVER("Execlists enabled for %s\n", engine->name); /* After a GPU reset, we may have requests to replay */ + clear_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted); if (!execlists_elsp_idle(engine)) { engine->execlist_port[0].count = 0; engine->execlist_port[1].count = 0; diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h index a9ea84ea3155..8e872730f8eb 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.h +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h @@ -213,6 +213,7 @@ struct intel_engine_cs { unsigned long irq_posted; #define ENGINE_IRQ_BREADCRUMB 0 +#define ENGINE_IRQ_EXECLIST 1 /* Rather than have every client wait upon all user interrupts, * with the herd waking after every interrupt and each doing the -- 2.20.1