[igt-dev] [PATCH i-g-t 2/7] lib/intel_batchbuffer: Detect and use kernel alignment capability

[Zbigniew Kempczyński]

For gens where relocations are supported kernel can set object offset
everywhere it wants but it honours the alignment setting.

For gens where we got no relocations and setting alignment is not
allowed in exec object we want to ensure allocator will still use it
to properly align the offset.

Detect kernel caps in alignment setting and use it for reloc/no-reloc
paths accordingly.

v2: rename to gem_allows_obj_alignment() (Ashutosh)

Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
Cc: Petri Latvala <petri.latvala at intel.com>
Cc: Ashutosh Dixit <ashutosh.dixit at intel.com>
---
 lib/intel_batchbuffer.c | 9 +++++++--
 lib/intel_batchbuffer.h | 1 +
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/lib/intel_batchbuffer.c b/lib/intel_batchbuffer.c
index 9c26fe207..6fc81400a 100644
--- a/lib/intel_batchbuffer.c
+++ b/lib/intel_batchbuffer.c
@@ -1335,6 +1335,7 @@ __intel_bb_create(int i915, uint32_t ctx, uint32_t size, bool do_relocs,
 
 	igt_assert(ibb);
 
+	ibb->allows_obj_alignment = gem_allows_obj_alignment(i915);
 	ibb->uses_full_ppgtt = gem_uses_full_ppgtt(i915);
 	ibb->devid = intel_get_drm_devid(i915);
 	ibb->gen = intel_gen(ibb->devid);
@@ -1783,6 +1784,7 @@ __add_to_cache(struct intel_bb *ibb, uint32_t handle)
 	igt_assert(object);
 
 	object->handle = handle;
+	object->alignment = 0;
 	found = tsearch((void *) object, &ibb->root, __compare_objects);
 
 	if (*found == object) {
@@ -1905,7 +1907,7 @@ intel_bb_add_object(struct intel_bb *ibb, uint32_t handle, uint64_t size,
 		   || ALIGN(offset, alignment) == offset);
 
 	object = __add_to_cache(ibb, handle);
-	object->alignment = alignment ?: 4096;
+	alignment = alignment ?: 4096;
 	__add_to_objects(ibb, object);
 
 	/*
@@ -1917,7 +1919,7 @@ intel_bb_add_object(struct intel_bb *ibb, uint32_t handle, uint64_t size,
 	if (INVALID_ADDR(object->offset)) {
 		if (INVALID_ADDR(offset)) {
 			offset = __intel_bb_get_offset(ibb, handle, size,
-						       object->alignment);
+						       alignment);
 		} else {
 			offset = offset & (ibb->gtt_size - 1);
 
@@ -1962,6 +1964,9 @@ intel_bb_add_object(struct intel_bb *ibb, uint32_t handle, uint64_t size,
 	if (ibb->uses_full_ppgtt && !ibb->enforce_relocs)
 		object->flags |= EXEC_OBJECT_PINNED;
 
+	if (ibb->allows_obj_alignment)
+		object->alignment = alignment;
+
 	return object;
 }
 
diff --git a/lib/intel_batchbuffer.h b/lib/intel_batchbuffer.h
index 58bddb1a1..e76063075 100644
--- a/lib/intel_batchbuffer.h
+++ b/lib/intel_batchbuffer.h
@@ -476,6 +476,7 @@ struct intel_bb {
 	uint64_t gtt_size;
 	bool supports_48b_address;
 	bool uses_full_ppgtt;
+	bool allows_obj_alignment;
 
 	struct igt_pxp pxp;
 	uint32_t ctx;
-- 
2.26.0