Hi
Am 28.12.25 um 01:53 schrieb Dmitry Baryshkov:
On Thu, Dec 11, 2025 at 08:46:26AM +0100, Thomas Zimmermann wrote:
Hi
Am 10.12.25 um 20:42 schrieb Dmitry Baryshkov:
The function drm_property_replace_blob_from_id() allows checking whether
the blob size is equal to a predefined value. In case of variable-size
properties (like the gamma / degamma LUTs) we might want to check for
the blob size against the maximum, allowing properties of the size
lesser than the max supported by the hardware. Extend the function in
order to support such checks.
Signed-off-by: Dmitry Baryshkov <[email protected]>
---
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c | 5 +++++
drivers/gpu/drm/drm_atomic_uapi.c | 7 +++++--
drivers/gpu/drm/drm_property.c | 11 +++++++++++
include/drm/drm_property.h | 1 +
4 files changed, 22 insertions(+), 2 deletions(-)
@@ -801,6 +803,15 @@ int drm_property_replace_blob_from_id(struct drm_device
*dev,
drm_property_blob_put(new_blob);
return -EINVAL;
}
+
+ if (max_size > 0 &&
+ new_blob->length > max_size) {
+ drm_dbg_atomic(dev,
+ "[BLOB:%d] length %zu greater than max
%zu\n",
+ new_blob->base.id, new_blob->length,
max_size);
+ drm_property_blob_put(new_blob);
+ return -EINVAL;
+ }
I'd first test for max_size before testing for expected size.
And shouldn't you also test for (max_size % expected_elem_size == 0)?
No, why? We are testing the values passed from the userspace, not the
kernel itself. E.g. we also don't have a test that (expected_size %
expected_elem_size == 0).
Well, OK.
Best regards
Thomas
Best regards
Thomas
}
*replaced |= drm_property_replace_blob(blob, new_blob);
diff --git a/include/drm/drm_property.h b/include/drm/drm_property.h
index 082f29156b3e..aa49b5a42bb5 100644
--- a/include/drm/drm_property.h
+++ b/include/drm/drm_property.h
@@ -284,6 +284,7 @@ int drm_property_replace_blob_from_id(struct drm_device
*dev,
uint64_t blob_id,
ssize_t expected_size,
ssize_t expected_elem_size,
+ ssize_t max_size,
bool *replaced);
int drm_property_replace_global_blob(struct drm_device *dev,
struct drm_property_blob **replace,
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)
