[Intel-gfx] [PATCH 1/5] drm/i915: Avoid invariant conditionals in lrc interrupt handler

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

There is no point in doing several gen and static feature dependant
branches multiple times per interrupt handled. Do them once on
ring setup and use the cached values.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/intel_lrc.c        | 34 +++++++++++++++++----------------
 drivers/gpu/drm/i915/intel_ringbuffer.h |  2 ++
 2 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 06180dce954e..ea031bb46909 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -293,29 +293,15 @@ uint64_t intel_lr_context_descriptor(struct intel_context *ctx,
 				     struct intel_engine_cs *ring)
 {
 	struct drm_i915_gem_object *ctx_obj = ctx->engine[ring->id].state;
-	uint64_t desc;
+	uint64_t desc = ring->ctx_desc_template;
 	uint64_t lrca = i915_gem_obj_ggtt_offset(ctx_obj) +
 			LRC_PPHWSP_PN * PAGE_SIZE;
 
 	WARN_ON(lrca & 0xFFFFFFFF00000FFFULL);
 
-	desc = GEN8_CTX_VALID;
-	desc |= GEN8_CTX_ADDRESSING_MODE(dev) << GEN8_CTX_ADDRESSING_MODE_SHIFT;
-	if (IS_GEN8(ctx_obj->base.dev))
-		desc |= GEN8_CTX_L3LLC_COHERENT;
-	desc |= GEN8_CTX_PRIVILEGE;
 	desc |= lrca;
 	desc |= (u64)intel_execlists_ctx_id(ctx_obj) << GEN8_CTX_ID_SHIFT;
 
-	/* TODO: WaDisableLiteRestore when we start using semaphore
-	 * signalling between Command Streamers */
-	/* desc |= GEN8_CTX_FORCE_RESTORE; */
-
-	/* WaEnableForceRestoreInCtxtDescForVCS:skl */
-	/* WaEnableForceRestoreInCtxtDescForVCS:bxt */
-	if (disable_lite_restore_wa(ring))
-		desc |= GEN8_CTX_FORCE_RESTORE;
-
 	return desc;
 }
 
@@ -540,7 +526,7 @@ void intel_lrc_irq_handler(struct intel_engine_cs *ring)
 		}
 	}
 
-	if (disable_lite_restore_wa(ring)) {
+	if (ring->disable_lite_restore_wa) {
 		/* Prevent a ctx to preempt itself */
 		if ((status & GEN8_CTX_STATUS_ACTIVE_IDLE) &&
 		    (submit_contexts != 0))
@@ -1948,6 +1934,22 @@ static int logical_ring_init(struct drm_device *dev, struct intel_engine_cs *rin
 		return ret;
 	}
 
+	ring->disable_lite_restore_wa = disable_lite_restore_wa(ring);
+
+	ring->ctx_desc_template = GEN8_CTX_VALID;
+	ring->ctx_desc_template |= GEN8_CTX_ADDRESSING_MODE(dev) <<
+				   GEN8_CTX_ADDRESSING_MODE_SHIFT;
+	if (IS_GEN8(dev))
+		ring->ctx_desc_template |= GEN8_CTX_L3LLC_COHERENT;
+	ring->ctx_desc_template |= GEN8_CTX_PRIVILEGE;
+
+	/* TODO: WaDisableLiteRestore when we start using semaphore
+	 * signalling between Command Streamers */
+	/* WaEnableForceRestoreInCtxtDescForVCS:skl */
+	/* WaEnableForceRestoreInCtxtDescForVCS:bxt */
+	if (ring->disable_lite_restore_wa)
+		ring->ctx_desc_template |= GEN8_CTX_FORCE_RESTORE;
+
 	return ret;
 }
 
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 58b1976a7d0a..ad9cd6d73ab5 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -268,6 +268,8 @@ struct  intel_engine_cs {
 	struct list_head execlist_queue;
 	struct list_head execlist_retired_req_list;
 	u8 next_context_status_buffer;
+	bool disable_lite_restore_wa;
+	u32 ctx_desc_template;
 	u32             irq_keep_mask; /* bitmask for interrupts that should not be masked */
 	int		(*emit_request)(struct drm_i915_gem_request *request);
 	int		(*emit_flush)(struct drm_i915_gem_request *request,
-- 
1.9.1