On 2/11/22 10:52, Matthew Auld wrote:
On Fri, 11 Feb 2022 at 09:49, Thomas Hellström
<thomas.hellstrom@xxxxxxxxxxxxxxx> wrote:
On 2/10/22 13:13, 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..cc9ddb943f96 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_GPU_ONLY;
+
WRT previous review comment here, it would be easier to follow if the bo
was marked as a GPU only buffer regardless. Then for example capture and
other functions where it actually matters can choose to take action
based on, for example, whether the BAR is restricted or not?
Yeah, I completely forgot about this, sorry. Will fix now.
Actually you did reply, but I forgot to reply to that :).
/Thomas
