[PATCH v3 13/25] drm/msm: Compute dumb-buffer sizes with drm_mode_size_dumb()

Thomas Zimmermann
2025-02-18T14:27:09Z

Call drm_mode_size_dumb() to compute dumb-buffer scanline pitch
and buffer size. Alignment is specified in bytes, but the hardware
requires the scanline pitch to be a multiple of 32 pixels. Therefore
compute the byte size of 32 pixels in the given color mode and align
the pitch accordingly. This replaces the existing code in the driver's
align_pitch() helper.

v3:
- clarify pitch alignment in commit message (Dmitry)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Sean Paul <sean@poorly.run>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
---
drivers/gpu/drm/msm/msm_gem.c | 27 +++++++++++++++++++++++++--
1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index ebc9ba66efb8..a956905f1ef2 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -11,8 +11,10 @@
#include <linux/dma-buf.h>
#include <linux/pfn_t.h>

+#include <drm/drm_dumb_buffers.h>
#include <drm/drm_prime.h>
#include <drm/drm_file.h>
+#include <drm/drm_fourcc.h>

#include <trace/events/gpu_mem.h>

@@ -700,8 +702,29 @@ void msm_gem_unpin_iova(struct drm_gem_object *obj,
int msm_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
struct drm_mode_create_dumb *args)
{
- args->pitch = align_pitch(args->width, args->bpp);
- args->size = PAGE_ALIGN(args->pitch * args->height);
+ u32 fourcc;
+ const struct drm_format_info *info;
+ u64 pitch_align;
+ int ret;
+
+ /*
+ * Adreno needs pitch aligned to 32 pixels. Compute the number
+ * of bytes for a block of 32 pixels at the given color format.
+ * Use the result as pitch alignment.
+ */
+ fourcc = drm_driver_color_mode_format(dev, 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_32);
+ if (!pitch_align || pitch_align > U32_MAX)
+ return -EINVAL;
+ ret = drm_mode_size_dumb(dev, args, pitch_align, 0);
+ if (ret)
+ return ret;
+
return msm_gem_new_handle(dev, file, args->size,
MSM_BO_SCANOUT | MSM_BO_WC, &args->handle, "dumb");
}
--
2.48.1