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From 3fef5cda970124a15c553c1672d800e40fc08a9e Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon, 20 Nov 2017 10:20:02 +0000
Subject: [PATCH] drm/i915: Automatic i915_switch_context for legacy
Git-commit: 3fef5cda970124a15c553c1672d800e40fc08a9e
Patch-mainline: v4.16-rc1
References: FATE#322643 bsc#1055900

During request construction, after pinning the context we know whether
or not we have to emit a context switch. So move this common operation
from every caller into i915_gem_request_alloc() itself.

V2: Always submit the request if we emitted some commands during request
construction, as typically it also involves changes in global state.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171120102002.22254-2-chris@chris-wilson.co.uk
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/i915/i915_gem.c                   |    2 +-
 drivers/gpu/drm/i915/i915_gem_context.c           |    7 +------
 drivers/gpu/drm/i915/i915_gem_execbuffer.c        |    8 --------
 drivers/gpu/drm/i915/i915_gem_request.c           |    4 ++++
 drivers/gpu/drm/i915/i915_perf.c                  |    3 +--
 drivers/gpu/drm/i915/intel_ringbuffer.c           |    4 ++++
 drivers/gpu/drm/i915/selftests/huge_pages.c       |   10 +++-------
 drivers/gpu/drm/i915/selftests/i915_gem_context.c |    4 ----
 drivers/gpu/drm/i915/selftests/i915_gem_request.c |   10 ----------
 drivers/gpu/drm/i915/selftests/intel_hangcheck.c  |    5 -----
 10 files changed, 14 insertions(+), 43 deletions(-)

--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -5040,7 +5040,7 @@ static int __intel_engines_record_defaul
 			goto out_ctx;
 		}
 
-		err = i915_switch_context(rq);
+		err = 0;
 		if (engine->init_context)
 			err = engine->init_context(rq);
 
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -842,8 +842,7 @@ int i915_switch_context(struct drm_i915_
 	struct intel_engine_cs *engine = req->engine;
 
 	lockdep_assert_held(&req->i915->drm.struct_mutex);
-	if (i915_modparams.enable_execlists)
-		return 0;
+	GEM_BUG_ON(i915_modparams.enable_execlists);
 
 	if (!req->ctx->engine[engine->id].state) {
 		struct i915_gem_context *to = req->ctx;
@@ -899,7 +898,6 @@ int i915_gem_switch_to_kernel_context(st
 
 	for_each_engine(engine, dev_priv, id) {
 		struct drm_i915_gem_request *req;
-		int ret;
 
 		if (engine_has_idle_kernel_context(engine))
 			continue;
@@ -922,10 +920,7 @@ int i915_gem_switch_to_kernel_context(st
 								 GFP_KERNEL);
 		}
 
-		ret = i915_switch_context(req);
 		i915_add_request(req);
-		if (ret)
-			return ret;
 	}
 
 	return 0;
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1111,10 +1111,6 @@ static int __reloc_gpu_alloc(struct i915
 	if (err)
 		goto err_request;
 
-	err = i915_switch_context(rq);
-	if (err)
-		goto err_request;
-
 	err = eb->engine->emit_bb_start(rq,
 					batch->node.start, PAGE_SIZE,
 					cache->gen > 5 ? 0 : I915_DISPATCH_SECURE);
@@ -1960,10 +1956,6 @@ static int eb_submit(struct i915_execbuf
 	if (err)
 		return err;
 
-	err = i915_switch_context(eb->request);
-	if (err)
-		return err;
-
 	if (eb->args->flags & I915_EXEC_GEN7_SOL_RESET) {
 		err = i915_reset_gen7_sol_offsets(eb->request);
 		if (err)
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -624,6 +624,10 @@ i915_gem_request_alloc(struct intel_engi
 	if (ret)
 		goto err_unpin;
 
+	ret = intel_ring_wait_for_space(ring, MIN_SPACE_FOR_ADD_REQUEST);
+	if (ret)
+		goto err_unreserve;
+
 	/* Move the oldest request to the slab-cache (if not in use!) */
 	req = list_first_entry_or_null(&engine->timeline->requests,
 				       typeof(*req), link);
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -1726,10 +1726,9 @@ static int gen8_switch_to_updated_kernel
 							 GFP_KERNEL);
 	}
 
-	ret = i915_switch_context(req);
 	i915_add_request(req);
 
-	return ret;
+	return 0;
 }
 
 /*
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1592,6 +1592,10 @@ static int ring_request_alloc(struct drm
 	if (ret)
 		return ret;
 
+	ret = i915_switch_context(request);
+	if (ret)
+		return ret;
+
 	request->reserved_space -= LEGACY_REQUEST_SIZE;
 	return 0;
 }
--- a/drivers/gpu/drm/i915/selftests/huge_pages.c
+++ b/drivers/gpu/drm/i915/selftests/huge_pages.c
@@ -989,13 +989,9 @@ static int gpu_write(struct i915_vma *vm
 	i915_vma_unpin(batch);
 	i915_vma_close(batch);
 
-	err = i915_switch_context(rq);
-	if (err)
-		goto err_request;
-
-	err = rq->engine->emit_bb_start(rq,
-					batch->node.start, batch->node.size,
-					flags);
+	err = engine->emit_bb_start(rq,
+				    batch->node.start, batch->node.size,
+				    flags);
 	if (err)
 		goto err_request;
 
--- a/drivers/gpu/drm/i915/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
@@ -158,10 +158,6 @@ static int gpu_fill(struct drm_i915_gem_
 		goto err_batch;
 	}
 
-	err = i915_switch_context(rq);
-	if (err)
-		goto err_request;
-
 	flags = 0;
 	if (INTEL_GEN(vm->i915) <= 5)
 		flags |= I915_DISPATCH_SECURE;
--- a/drivers/gpu/drm/i915/selftests/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_request.c
@@ -459,10 +459,6 @@ empty_request(struct intel_engine_cs *en
 	if (IS_ERR(request))
 		return request;
 
-	err = i915_switch_context(request);
-	if (err)
-		goto out_request;
-
 	err = engine->emit_bb_start(request,
 				    batch->node.start,
 				    batch->node.size,
@@ -671,9 +667,6 @@ static int live_all_engines(void *arg)
 			goto out_request;
 		}
 
-		err = i915_switch_context(request[id]);
-		GEM_BUG_ON(err);
-
 		err = engine->emit_bb_start(request[id],
 					    batch->node.start,
 					    batch->node.size,
@@ -790,9 +783,6 @@ static int live_sequential_engines(void
 			}
 		}
 
-		err = i915_switch_context(request[id]);
-		GEM_BUG_ON(err);
-
 		err = engine->emit_bb_start(request[id],
 					    batch->node.start,
 					    batch->node.size,
--- a/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
+++ b/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
@@ -114,10 +114,6 @@ static int emit_recurse_batch(struct han
 	if (err)
 		goto unpin_vma;
 
-	err = i915_switch_context(rq);
-	if (err)
-		goto unpin_hws;
-
 	i915_vma_move_to_active(vma, rq, 0);
 	if (!i915_gem_object_has_active_reference(vma->obj)) {
 		i915_gem_object_get(vma->obj);
@@ -169,7 +165,6 @@ static int emit_recurse_batch(struct han
 
 	err = rq->engine->emit_bb_start(rq, vma->node.start, PAGE_SIZE, flags);
 
-unpin_hws:
 	i915_vma_unpin(hws);
 unpin_vma:
 	i915_vma_unpin(vma);