On 8/21/25 10:17, 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. > > v5: > - avoid reset of arguments (Tomi) > > Signed-off-by: Thomas Zimmermann <[email protected]> > Reviewed-by: Tomi Valkeinen <[email protected]> > --- > drivers/gpu/drm/drm_gem_dma_helper.c | 7 +++++-- > drivers/gpu/drm/imx/ipuv3/imx-drm-core.c | 4 +++- > 2 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/drm_gem_dma_helper.c > b/drivers/gpu/drm/drm_gem_dma_helper.c > index 4f0320df858f..ab1a70b1d6f1 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;
Hi, Was it intentional for this change to alter the pitch? The alignment requirement has been updated—from 8-bit alignment to 64-bit alignment. Since the pitch is expressed in bytes, we should pass SZ_1 instead of SZ_8 for hw_patch_align. For example, for an 850×480 framebuffer at 16 bpp, the pitch should be 1700 bytes. With the new alignment, the pitch becomes 1704 bytes. Please let me know if you’d like me to submit a fix. Regards, Ludovic > > 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..af4a30311e18 100644 > --- a/drivers/gpu/drm/imx/ipuv3/imx-drm-core.c > +++ b/drivers/gpu/drm/imx/ipuv3/imx-drm-core.c > @@ -145,8 +145,10 @@ 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); > + ret = drm_gem_dma_dumb_create_internal(file_priv, drm, args); > if (ret) > return ret; >
