Nouveau - Feb 2025 - [PATCH v3 06/25] drm/armada: Compute dumb-buffer sizes with drm_mode_size_dumb()

Call drm_mode_size_dumb() to compute dumb-buffer scanline pitch and
buffer size. No alignment required.

Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
Cc: Russell King <linux at armlinux.org.uk>
---
 drivers/gpu/drm/armada/armada_gem.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/armada/armada_gem.c
b/drivers/gpu/drm/armada/armada_gem.c
index 1a1680d71486..0f11ae06064a 100644
--- a/drivers/gpu/drm/armada/armada_gem.c
+++ b/drivers/gpu/drm/armada/armada_gem.c
@@ -9,6 +9,7 @@
 #include <linux/shmem_fs.h>
 
 #include <drm/armada_drm.h>
+#include <drm/drm_dumb_buffers.h>
 #include <drm/drm_prime.h>
 
 #include "armada_drm.h"
@@ -244,14 +245,13 @@ int armada_gem_dumb_create(struct drm_file *file, struct
drm_device *dev,
 	struct drm_mode_create_dumb *args)
 {
 	struct armada_gem_object *dobj;
-	u32 handle;
-	size_t size;
 	int ret;
 
-	args->pitch = armada_pitch(args->width, args->bpp);
-	args->size = size = args->pitch * args->height;
+	ret = drm_mode_size_dumb(dev, args, 0, 0);
+	if (ret)
+		return ret;
 
-	dobj = armada_gem_alloc_private_object(dev, size);
+	dobj = armada_gem_alloc_private_object(dev, args->size);
 	if (dobj == NULL)
 		return -ENOMEM;
 
@@ -259,14 +259,12 @@ int armada_gem_dumb_create(struct drm_file *file, struct
drm_device *dev,
 	if (ret)
 		goto err;
 
-	ret = drm_gem_handle_create(file, &dobj->obj, &handle);
+	ret = drm_gem_handle_create(file, &dobj->obj, &args->handle);
 	if (ret)
 		goto err;
 
-	args->handle = handle;
-
 	/* drop reference from allocate - handle holds it now */
-	DRM_DEBUG_DRIVER("obj %p size %zu handle %#x\n", dobj, size,
handle);
+	DRM_DEBUG_DRIVER("obj %p size %llu handle %#x\n", dobj,
args->size, args->handle);
  err:
 	drm_gem_object_put(&dobj->obj);
 	return ret;
-- 
2.48.1

On Tue, Feb 18, 2025 at 03:23:29PM +0100, Thomas Zimmermann
wrote:
> Call drm_mode_size_dumb() to compute dumb-buffer scanline pitch and
> buffer size. No alignment required.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> Cc: Russell King <linux at armlinux.org.uk>
armada_pitch() does have some special alignment (it aligns the pitch to
128 bytes). I've no idea what drm_mode_size_dumb() does. Can you check
whether it does the same please?

If it doesn't, then this patch is incorrect.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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