[v5] drm/dumb-buffers: Fix and improve buffer-size calculation

[PATCH v5 25/25] drm/xlnx: Compute dumb-buffer sizes with drm_mode_size_dumb()

Posted by Thomas Zimmermann 4 months, 2 weeks ago

Call drm_mode_size_dumb() to compute dumb-buffer scanline pitch and
buffer size. Align the pitch according to hardware requirements.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/xlnx/zynqmp_kms.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xlnx/zynqmp_kms.c b/drivers/gpu/drm/xlnx/zynqmp_kms.c
index b47463473472..7ea0cd4f71d3 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_kms.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_kms.c
@@ -19,6 +19,7 @@
 #include <drm/drm_crtc.h>
 #include <drm/drm_device.h>
 #include <drm/drm_drv.h>
+#include <drm/drm_dumb_buffers.h>
 #include <drm/drm_encoder.h>
 #include <drm/drm_fbdev_dma.h>
 #include <drm/drm_fourcc.h>
@@ -363,10 +364,12 @@ static int zynqmp_dpsub_dumb_create(struct drm_file *file_priv,
 				    struct drm_mode_create_dumb *args)
 {
 	struct zynqmp_dpsub *dpsub = to_zynqmp_dpsub(drm);
-	unsigned int pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
+	int ret;
 
 	/* Enforce the alignment constraints of the DMA engine. */
-	args->pitch = ALIGN(pitch, dpsub->dma_align);
+	ret = drm_mode_size_dumb(drm, args, dpsub->dma_align, 0);
+	if (ret)
+		return ret;
 
 	return drm_gem_dma_dumb_create_internal(file_priv, drm, args);
 }
-- 
2.49.0

Re: [PATCH v5 25/25] drm/xlnx: Compute dumb-buffer sizes with drm_mode_size_dumb()

Posted by Tomi Valkeinen 2 months, 3 weeks ago

On 13/06/2025 12:00, Thomas Zimmermann wrote:
> Call drm_mode_size_dumb() to compute dumb-buffer scanline pitch and
> buffer size. Align the pitch according to hardware requirements.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
>  drivers/gpu/drm/xlnx/zynqmp_kms.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xlnx/zynqmp_kms.c b/drivers/gpu/drm/xlnx/zynqmp_kms.c
> index b47463473472..7ea0cd4f71d3 100644
> --- a/drivers/gpu/drm/xlnx/zynqmp_kms.c
> +++ b/drivers/gpu/drm/xlnx/zynqmp_kms.c
> @@ -19,6 +19,7 @@
>  #include <drm/drm_crtc.h>
>  #include <drm/drm_device.h>
>  #include <drm/drm_drv.h>
> +#include <drm/drm_dumb_buffers.h>
>  #include <drm/drm_encoder.h>
>  #include <drm/drm_fbdev_dma.h>
>  #include <drm/drm_fourcc.h>
> @@ -363,10 +364,12 @@ static int zynqmp_dpsub_dumb_create(struct drm_file *file_priv,
>  				    struct drm_mode_create_dumb *args)
>  {
>  	struct zynqmp_dpsub *dpsub = to_zynqmp_dpsub(drm);
> -	unsigned int pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
> +	int ret;
>  
>  	/* Enforce the alignment constraints of the DMA engine. */
> -	args->pitch = ALIGN(pitch, dpsub->dma_align);
> +	ret = drm_mode_size_dumb(drm, args, dpsub->dma_align, 0);
> +	if (ret)
> +		return ret;
>  
>  	return drm_gem_dma_dumb_create_internal(file_priv, drm, args);
>  }

Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

 Tomi

Re: [PATCH v5 25/25] drm/xlnx: Compute dumb-buffer sizes with drm_mode_size_dumb()

Posted by Laurent Pinchart 4 months, 2 weeks ago

Hi Thomas,

Thank you for the patch.

On Fri, Jun 13, 2025 at 11:00:44AM +0200, Thomas Zimmermann wrote:
> Call drm_mode_size_dumb() to compute dumb-buffer scanline pitch and
> buffer size. Align the pitch according to hardware requirements.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/gpu/drm/xlnx/zynqmp_kms.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xlnx/zynqmp_kms.c b/drivers/gpu/drm/xlnx/zynqmp_kms.c
> index b47463473472..7ea0cd4f71d3 100644
> --- a/drivers/gpu/drm/xlnx/zynqmp_kms.c
> +++ b/drivers/gpu/drm/xlnx/zynqmp_kms.c
> @@ -19,6 +19,7 @@
>  #include <drm/drm_crtc.h>
>  #include <drm/drm_device.h>
>  #include <drm/drm_drv.h>
> +#include <drm/drm_dumb_buffers.h>
>  #include <drm/drm_encoder.h>
>  #include <drm/drm_fbdev_dma.h>
>  #include <drm/drm_fourcc.h>
> @@ -363,10 +364,12 @@ static int zynqmp_dpsub_dumb_create(struct drm_file *file_priv,
>  				    struct drm_mode_create_dumb *args)
>  {
>  	struct zynqmp_dpsub *dpsub = to_zynqmp_dpsub(drm);
> -	unsigned int pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
> +	int ret;
>  
>  	/* Enforce the alignment constraints of the DMA engine. */
> -	args->pitch = ALIGN(pitch, dpsub->dma_align);
> +	ret = drm_mode_size_dumb(drm, args, dpsub->dma_align, 0);
> +	if (ret)
> +		return ret;
>  
>  	return drm_gem_dma_dumb_create_internal(file_priv, drm, args);
>  }

-- 
Regards,

Laurent Pinchart