From 5af05fefb5be51d42effc4f802b6d806fbda34eb Mon Sep 17 00:00:00 2001 From: Michel Thierry Date: Fri, 4 Sep 2015 12:59:15 +0100 Subject: [PATCH] drm/i915/lrc: Prevent preemption when lite-restore is disabled When WaEnableForceRestoreInCtxtDescForVCS is required, it is only safe to send new contexts if the last reported event is "active to idle". Otherwise the same context can fully preempt itself because lite-restore is disabled. Testcase: igt/gem_concurrent_blit Reported-by: Daniele Ceraolo Spurio Signed-off-by: Michel Thierry Reviewed-by: Arun Siluvery Tested-by: Daniele Ceraolo Spurio Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_lrc.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index d8b605fc4aa9..c3fca4be7a8c 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -277,10 +277,18 @@ u32 intel_execlists_ctx_id(struct drm_i915_gem_object *ctx_obj) return lrca >> 12; } +static bool disable_lite_restore_wa(struct intel_engine_cs *ring) +{ + struct drm_device *dev = ring->dev; + + return ((IS_SKYLAKE(dev) && INTEL_REVID(dev) <= SKL_REVID_B0) || + (IS_BROXTON(dev) && INTEL_REVID(dev) == BXT_REVID_A0)) && + (ring->id == VCS || ring->id == VCS2); +} + uint64_t intel_lr_context_descriptor(struct intel_context *ctx, struct intel_engine_cs *ring) { - struct drm_device *dev = ring->dev; struct drm_i915_gem_object *ctx_obj = ctx->engine[ring->id].state; uint64_t desc; uint64_t lrca = i915_gem_obj_ggtt_offset(ctx_obj) + @@ -302,9 +310,7 @@ uint64_t intel_lr_context_descriptor(struct intel_context *ctx, /* WaEnableForceRestoreInCtxtDescForVCS:skl */ /* WaEnableForceRestoreInCtxtDescForVCS:bxt */ - if (((IS_SKYLAKE(dev) && INTEL_REVID(dev) <= SKL_REVID_B0) || - (IS_BROXTON(dev) && INTEL_REVID(dev) == BXT_REVID_A0)) && - (ring->id == VCS || ring->id == VCS2)) + if (disable_lite_restore_wa(ring)) desc |= GEN8_CTX_FORCE_RESTORE; return desc; @@ -495,7 +501,7 @@ void intel_lrc_irq_handler(struct intel_engine_cs *ring) u32 status_pointer; u8 read_pointer; u8 write_pointer; - u32 status; + u32 status = 0; u32 status_id; u32 submit_contexts = 0; @@ -533,8 +539,14 @@ void intel_lrc_irq_handler(struct intel_engine_cs *ring) } } - if (submit_contexts != 0) + if (disable_lite_restore_wa(ring)) { + /* Prevent a ctx to preempt itself */ + if ((status & GEN8_CTX_STATUS_ACTIVE_IDLE) && + (submit_contexts != 0)) + execlists_context_unqueue(ring); + } else if (submit_contexts != 0) { execlists_context_unqueue(ring); + } spin_unlock(&ring->execlist_lock); -- 2.20.1