drm/i915: Automatic i915_switch_context for legacy

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

4 files changed, 3 insertions, 26 deletions

diff --git a/drivers/gpu/drm/i915/selftests/huge_pages.c b/drivers/gpu/drm/i915/selftests/huge_pages.c
index 159a2cb..db7a0a1 100644
--- 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 *vma,
 	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;
 
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
index 4ff30b9..09340b3 100644
--- 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_object *obj,
 		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;
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_request.c b/drivers/gpu/drm/i915/selftests/i915_gem_request.c
index d7bf53f..647bf2b 100644
--- 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 *engine,
 	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 *arg)
 			}
 		}
 
-		err = i915_switch_context(request[id]);
-		GEM_BUG_ON(err);
-
 		err = engine->emit_bb_start(request[id],
 					    batch->node.start,
 					    batch->node.size,
diff --git a/drivers/gpu/drm/i915/selftests/intel_hangcheck.c b/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
index 145bdc2..1bbb8c4 100644
--- 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 hang *h,
 	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 hang *h,
 
 	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);