Hi,
On 11/03/2025 17:47, Thomas Zimmermann wrote:
> Call drm_mode_size_dumb() to compute dumb-buffer scanline pitch and
> buffer size. Align the pitch to a multiple of 8.
>
> Push the current calculation into the only direct caller imx. Imx's
> hardware requires the framebuffer width to be aligned to 8. The
> driver's current approach is actually incorrect, as it only guarantees
> this implicitly and requires bpp to be a multiple of 8 already. A
> later commit will fix this problem by aligning the scanline pitch
> such that an aligned width still fits into each scanline's memory.
>
> A number of other drivers are build on top of gem-dma helpers and
> implement their own dumb-buffer allocation. These drivers invoke
> drm_gem_dma_dumb_create_internal(), which is not affected by this
> commit.
>
> Signed-off-by: Thomas Zimmermann <tzimmerm...@suse.de>
> ---
> drivers/gpu/drm/drm_gem_dma_helper.c | 7 +++++--
> drivers/gpu/drm/imx/ipuv3/imx-drm-core.c | 2 ++
> 2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_gem_dma_helper.c
> b/drivers/gpu/drm/drm_gem_dma_helper.c
> index b7f033d4352a..49be9b033610 100644
> --- a/drivers/gpu/drm/drm_gem_dma_helper.c
> +++ b/drivers/gpu/drm/drm_gem_dma_helper.c
> @@ -20,6 +20,7 @@
> #include <drm/drm.h>
> #include <drm/drm_device.h>
> #include <drm/drm_drv.h>
> +#include <drm/drm_dumb_buffers.h>
> #include <drm/drm_gem_dma_helper.h>
> #include <drm/drm_vma_manager.h>
>
> @@ -304,9 +305,11 @@ int drm_gem_dma_dumb_create(struct drm_file *file_priv,
> struct drm_mode_create_dumb *args)
> {
> struct drm_gem_dma_object *dma_obj;
> + int ret;
>
> - args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
> - args->size = args->pitch * args->height;
> + ret = drm_mode_size_dumb(drm, args, SZ_8, 0);
> + if (ret)
> + return ret;
>
> dma_obj = drm_gem_dma_create_with_handle(file_priv, drm, args->size,
> &args->handle);
> diff --git a/drivers/gpu/drm/imx/ipuv3/imx-drm-core.c
> b/drivers/gpu/drm/imx/ipuv3/imx-drm-core.c
> index ec5fd9a01f1e..e7025df7b978 100644
> --- a/drivers/gpu/drm/imx/ipuv3/imx-drm-core.c
> +++ b/drivers/gpu/drm/imx/ipuv3/imx-drm-core.c
> @@ -145,6 +145,8 @@ static int imx_drm_dumb_create(struct drm_file *file_priv,
> int ret;
>
> args->width = ALIGN(width, 8);
> + args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
> + args->size = args->pitch * args->height;
>
> ret = drm_gem_dma_dumb_create(file_priv, drm, args);
> if (ret)
Won't the pitch and size just be overwritten by the
drm_gem_dma_dumb_create() call?
Tomi
