[RFC,147/162] drm/i915/gt: Allocate default ctx objects in SMEM

Commit Message

Matthew Auld Nov. 27, 2020, 12:07 p.m. UTC

From: Venkata Ramana Nayana <[e-mail]>

If record default objects are created in LMEM and in suspend
pin the pages of obj (src) and use blitter for eviction. But
during request creation using blitter context and try to pin the same
default object, to restore the ctx with default HW values, will leads to
the dead lock situation. To avoid this, safe to keep these
objects in SMEM.

Signed-off-by: Venkata Ramana Nayana <[e-mail]>
Cc: Prathap Kumar Valsan <[e-mail]>
---
 .../drm/i915/gt/intel_execlists_submission.c  | 25 +++++++++++++------
 1 file changed, 18 insertions(+), 7 deletions(-)

Comments

Chris Wilson Nov. 27, 2020, 2:30 p.m. UTC | #1

Quoting Matthew Auld (2020-11-27 12:07:03)
> From: Venkata Ramana Nayana <[e-mail]>
> 
> If record default objects are created in LMEM and in suspend
> pin the pages of obj (src) and use blitter for eviction. But
> during request creation using blitter context and try to pin the same
> default object, to restore the ctx with default HW values, will leads to
> the dead lock situation. To avoid this, safe to keep these
> objects in SMEM.

Dead patch. Default object state should be recorded as shmemfs.
-Chris

Patch

diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
index c640b90711fd..ee5732b436e3 100644
--- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
+++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
@@ -4697,7 +4697,13 @@  static int __execlists_context_alloc(struct intel_context *ce,
 		context_size += PAGE_SIZE;
 	}
 
-	if (HAS_LMEM(engine->i915)) {
+	/* FIXME: temporary fix for allocating default ctx objects
+	 * in SMEM, to reslove suspend/resume issues while using
+	 * blitter based eviction. Will remove this once the upstream
+	 * changes merged, where default obj's stored using shmemfs file.
+	 */
+	if (HAS_LMEM(engine->i915) &&
+	    (!IS_DG1(engine->i915) || engine->default_state)) {
 		ctx_obj = i915_gem_object_create_lmem(engine->i915,
 						      context_size,
 						      I915_BO_ALLOC_CONTIGUOUS);
@@ -4707,16 +4713,18 @@  static int __execlists_context_alloc(struct intel_context *ce,
 	if (IS_ERR(ctx_obj))
 		return PTR_ERR(ctx_obj);
 
-	if (HAS_LMEM(engine->i915)) {
+	i915_gem_object_lock_isolated(ctx_obj);
+	if (HAS_LMEM(engine->i915) &&
+	    (!IS_DG1(engine->i915) || engine->default_state)) {
 		ret = context_clear_lmem(ctx_obj);
 		if (ret)
-			goto error_deref_obj;
+			goto error_unlock;
 	}
 
 	vma = i915_vma_instance(ctx_obj, &engine->gt->ggtt->vm, NULL);
 	if (IS_ERR(vma)) {
 		ret = PTR_ERR(vma);
-		goto error_deref_obj;
+		goto error_unlock;
 	}
 
 	if (!page_mask_bits(ce->timeline)) {
@@ -4732,7 +4740,7 @@  static int __execlists_context_alloc(struct intel_context *ce,
 			tl = intel_timeline_create(engine->gt);
 		if (IS_ERR(tl)) {
 			ret = PTR_ERR(tl);
-			goto error_deref_obj;
+			goto error_unlock;
 		}
 
 		ce->timeline = tl;
@@ -4741,15 +4749,18 @@  static int __execlists_context_alloc(struct intel_context *ce,
 	ring = intel_engine_create_ring(engine, (unsigned long)ce->ring);
 	if (IS_ERR(ring)) {
 		ret = PTR_ERR(ring);
-		goto error_deref_obj;
+		goto error_unlock;
 	}
 
 	ce->ring = ring;
 	ce->state = vma;
 
+	i915_gem_object_unlock(ctx_obj);
+
 	return 0;
 
-error_deref_obj:
+error_unlock:
+	i915_gem_object_unlock(ctx_obj);
 	i915_gem_object_put(ctx_obj);
 	return ret;
 }