[PATCH] drm/msm/dpu: fix UV scanlines calculation for YUV UBWC formats

From: Neil Armstrong

Date: Tue Apr 14 2026 - 11:14:43 EST


The UV scanlines is calculated with (height + 1) / 2 unlike
the Y scanlines, add back the correct scanlines calculation
for UBWC YUV formats.

Fixes: 2f3ff6ab8f5c ("drm/msm/dpu: use standard functions in _dpu_format_populate_plane_sizes_ubwc()")
Fixes: ada4a19ed21c ("drm/msm/dpu: rewrite _dpu_format_populate_plane_sizes_ubwc()")
Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
---
drivers/gpu/drm/msm/disp/dpu1/dpu_formats.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_formats.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_formats.c
index 6e8883dbfad4..590922c4f69b 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_formats.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_formats.c
@@ -61,7 +61,7 @@ static int _dpu_format_populate_plane_sizes_ubwc(
bool meta = MSM_FORMAT_IS_UBWC(fmt);

if (MSM_FORMAT_IS_YUV(fmt)) {
- unsigned int stride, sclines;
+ unsigned int stride, y_sclines, uv_sclines;
unsigned int y_tile_width, y_tile_height;
unsigned int y_meta_stride, y_meta_scanlines;
unsigned int uv_meta_stride, uv_meta_scanlines;
@@ -77,23 +77,25 @@ static int _dpu_format_populate_plane_sizes_ubwc(
y_tile_width = 32;
}

- sclines = round_up(fb->height, 16);
+ y_sclines = round_up(fb->height, 16);
+ uv_sclines = round_up((fb->height+1)>>1, 16);
y_tile_height = 4;
} else {
stride = round_up(fb->width, 128);
y_tile_width = 32;

- sclines = round_up(fb->height, 32);
+ y_sclines = round_up(fb->height, 32);
+ uv_sclines = round_up((fb->height+1)>>1, 32);
y_tile_height = 8;
}

layout->plane_pitch[0] = stride;
layout->plane_size[0] = round_up(layout->plane_pitch[0] *
- sclines, DPU_UBWC_PLANE_SIZE_ALIGNMENT);
+ y_sclines, DPU_UBWC_PLANE_SIZE_ALIGNMENT);

layout->plane_pitch[1] = stride;
layout->plane_size[1] = round_up(layout->plane_pitch[1] *
- sclines, DPU_UBWC_PLANE_SIZE_ALIGNMENT);
+ uv_sclines, DPU_UBWC_PLANE_SIZE_ALIGNMENT);

if (!meta)
return 0;

---
base-commit: 66672af7a095d89f082c5327f3b15bc2f93d558e
change-id: 20260414-topic-sm8x50-msm-dpu1-formats-qc10c-78b3919a715d

Best regards,
--
Neil Armstrong <neil.armstrong@xxxxxxxxxx>