[PATCH 1/3] drm/gem-dma: revert the 8-byte alignment constraint

Ludovic Desroches posted 3 patches 2 months, 2 weeks ago
[PATCH 1/3] drm/gem-dma: revert the 8-byte alignment constraint
Posted by Ludovic Desroches 2 months, 2 weeks ago
Using drm_mode_size_dumb() to compute the size of dumb buffers introduced
an 8-byte alignment constraint on the pitch that wasn’t present before.
Let’s remove this constraint, which isn’t necessarily required and may
cause buffers to be allocated larger than needed.

Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
---
 drivers/gpu/drm/drm_gem_dma_helper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_gem_dma_helper.c b/drivers/gpu/drm/drm_gem_dma_helper.c
index 12d8307997a0a90a9b5c0469bd742130fa6722d5..eb56ba2347966040a3c7fd27e09c8b81bc797daa 100644
--- a/drivers/gpu/drm/drm_gem_dma_helper.c
+++ b/drivers/gpu/drm/drm_gem_dma_helper.c
@@ -308,7 +308,7 @@ int drm_gem_dma_dumb_create(struct drm_file *file_priv,
 	struct drm_gem_dma_object *dma_obj;
 	int ret;
 
-	ret = drm_mode_size_dumb(drm, args, SZ_8, 0);
+	ret = drm_mode_size_dumb(drm, args, 0, 0);
 	if (ret)
 		return ret;
 

-- 
2.51.0

Re: [PATCH 1/3] drm/gem-dma: revert the 8-byte alignment constraint
Posted by Thomas Zimmermann 2 months, 1 week ago

Am 26.11.25 um 15:44 schrieb Ludovic Desroches:
> Using drm_mode_size_dumb() to compute the size of dumb buffers introduced
> an 8-byte alignment constraint on the pitch that wasn’t present before.
> Let’s remove this constraint, which isn’t necessarily required and may
> cause buffers to be allocated larger than needed.
>
> Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>

Fixes: dcacfcd35cef ("drm/gem-dma: Compute dumb-buffer sizes with 
drm_mode_size_dumb()")


> ---
>   drivers/gpu/drm/drm_gem_dma_helper.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_gem_dma_helper.c b/drivers/gpu/drm/drm_gem_dma_helper.c
> index 12d8307997a0a90a9b5c0469bd742130fa6722d5..eb56ba2347966040a3c7fd27e09c8b81bc797daa 100644
> --- a/drivers/gpu/drm/drm_gem_dma_helper.c
> +++ b/drivers/gpu/drm/drm_gem_dma_helper.c
> @@ -308,7 +308,7 @@ int drm_gem_dma_dumb_create(struct drm_file *file_priv,
>   	struct drm_gem_dma_object *dma_obj;
>   	int ret;
>   
> -	ret = drm_mode_size_dumb(drm, args, SZ_8, 0);
> +	ret = drm_mode_size_dumb(drm, args, 0, 0);
>   	if (ret)
>   		return ret;
>   
>

-- 
--
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)