[PATCH 3/5] drm/gem-dma: Use aligned default pitch and size for dumb buffers

[Thomas Zimmermann]

Use the pitch and size values stored in the args parameter for
allocating a dumb buffer in drm_gem_dma_dumb_create(). The values
come from drm_mode_create_dumb(). 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 <tzimmermann at 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 870b90b78bc4..0961e52893b9 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_align_dumb(args, 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 ced06bd8eae8..b3c9e8fcb45e 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)
-- 
2.47.0