[PATCH v3 10/25] drm/imx/ipuv3: Compute dumb-buffer sizes with drm_mode_size_dumb()

Thomas Zimmermann
2025-02-18T14:26:59Z

Call drm_mode_size_dumb() to compute dumb-buffer scanline pitch and
buffer size. The hardware requires the framebuffer width to be a
multiple of 8. The scanline pitch has be large enough to support
this. Therefore compute the byte size of 8 pixels in the given color
mode and align the pitch accordingly.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
---
drivers/gpu/drm/imx/ipuv3/imx-drm-core.c | 31 ++++++++++++++++++------
1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/imx/ipuv3/imx-drm-core.c b/drivers/gpu/drm/imx/ipuv3/imx-drm-core.c
index e7025df7b978..465b5a6ad5bb 100644
--- a/drivers/gpu/drm/imx/ipuv3/imx-drm-core.c
+++ b/drivers/gpu/drm/imx/ipuv3/imx-drm-core.c
@@ -17,7 +17,9 @@
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_drv.h>
+#include <drm/drm_dumb_buffers.h>
#include <drm/drm_fbdev_dma.h>
+#include <drm/drm_fourcc.h>
#include <drm/drm_gem_dma_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_managed.h>
@@ -141,19 +143,32 @@ static int imx_drm_dumb_create(struct drm_file *file_priv,
struct drm_device *drm,
struct drm_mode_create_dumb *args)
{
- u32 width = args->width;
+ u32 fourcc;
+ const struct drm_format_info *info;
+ u64 pitch_align;
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);
+ /*
+ * Hardware requires the framebuffer width to be aligned to
+ * multiples of 8. The mode-setting code handles this, but
+ * the buffer pitch has to be aligned as well. Set the pitch
+ * alignment accordingly, so that the each scanline fits into
+ * the allocated buffer.
+ */
+ fourcc = drm_driver_color_mode_format(drm, args->bpp);
+ if (fourcc == DRM_FORMAT_INVALID)
+ return -EINVAL;
+ info = drm_format_info(fourcc);
+ if (!info)
+ return -EINVAL;
+ pitch_align = drm_format_info_min_pitch(info, 0, SZ_8);
+ if (!pitch_align || pitch_align > U32_MAX)
+ return -EINVAL;
+ ret = drm_mode_size_dumb(drm, args, pitch_align, 0);
if (ret)
return ret;

- args->width = width;
- return ret;
+ return drm_gem_dma_dumb_create(file_priv, drm, args);
}

static const struct drm_driver imx_drm_driver = {
--
2.48.1