On 1/26/22 16:21, Matthew Auld wrote:
Starting from DG2+, when dealing with LMEM, we assume that by default
all userspace allocations should be placed in the non-mappable portion
of LMEM. Note that dumb buffers are not included here, since these are
not "GPU accelerated" and likely need CPU access.
In a later patch userspace will be able to provide a hint if CPU access
to the buffer is needed.
Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx>
Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/gem/i915_gem_create.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_create.c b/drivers/gpu/drm/i915/gem/i915_gem_create.c
index 9402d4bf4ffc..e7456443f163 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_create.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_create.c
@@ -424,6 +424,15 @@ i915_gem_create_ext_ioctl(struct drm_device *dev, void *data,
ext_data.n_placements = 1;
}
+ /*
+ * TODO: add a userspace hint to force CPU_ACCESS for the object, which
+ * can override this.
+ */
+ if (!IS_DG1(i915) && (ext_data.n_placements > 1 ||
+ ext_data.placements[0]->type !=
+ INTEL_MEMORY_SYSTEM))
+ ext_data.flags |= I915_BO_ALLOC_TOPDOWN;
Perhaps we should include DG1 here as well, so that the same paths are
taken regardless whether this is only a test on DG1?
+
obj = __i915_gem_object_create_user_ext(i915, args->size,
ext_data.placements,
ext_data.n_placements,
