On SC7280 targets, display modes with a width greater than the
max_mixer_width (2400) are rejected during mode validation when
merge3d is disabled. This limitation exists because, without a
3D merge block, two layer mixers cannot be combined(non-DSC interface),
preventing large layers from being split across mixers. As a result,
higher resolution modes cannot be supported.

Enable merge3d support on SC7280 to allow combining streams from
two layer mixers into a single non-DSC interface. This capability
removes the width restriction and enables buffer sizes beyond the
2400-pixel limit.

Fixes: 591e34a091d1 ("drm/msm/disp/dpu1: add support for display for SC7280 target")
Signed-off-by: Mahadevan P <mahadevan.p@oss.qualcomm.com>
---
Changes in v2:
  - Updated commit message for clarity (Dmitry).
---
 drivers/gpu/drm/msm/disp/dpu1/catalog/dpu_7_2_sc7280.h | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/catalog/dpu_7_2_sc7280.h b/drivers/gpu/drm/msm/disp/dpu1/catalog/dpu_7_2_sc7280.h
index 8f978b9c3452..2f8688224f34 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/catalog/dpu_7_2_sc7280.h
+++ b/drivers/gpu/drm/msm/disp/dpu1/catalog/dpu_7_2_sc7280.h
@@ -13,6 +13,7 @@ static const struct dpu_caps sc7280_dpu_caps = {
 	.has_dim_layer = true,
 	.has_idle_pc = true,
 	.max_linewidth = 2400,
+	.has_3d_merge = true,
 	.pixel_ram_size = DEFAULT_PIXEL_RAM_SIZE,
 };
 
@@ -134,17 +135,24 @@ static const struct dpu_pingpong_cfg sc7280_pp[] = {
 		.name = "pingpong_2", .id = PINGPONG_2,
 		.base = 0x6b000, .len = 0,
 		.sblk = &sc7280_pp_sblk,
-		.merge_3d = 0,
+		.merge_3d = MERGE_3D_1,
 		.intr_done = DPU_IRQ_IDX(MDP_SSPP_TOP0_INTR, 10),
 	}, {
 		.name = "pingpong_3", .id = PINGPONG_3,
 		.base = 0x6c000, .len = 0,
 		.sblk = &sc7280_pp_sblk,
-		.merge_3d = 0,
+		.merge_3d = MERGE_3D_1,
 		.intr_done = DPU_IRQ_IDX(MDP_SSPP_TOP0_INTR, 11),
 	},
 };
 
+static const struct dpu_merge_3d_cfg sc7280_merge_3d[] = {
+	{
+		.name = "merge_3d_1", .id = MERGE_3D_1,
+		.base = 0x4f000, .len = 0x8,
+	},
+};
+
 /* NOTE: sc7280 only has one DSC hard slice encoder */
 static const struct dpu_dsc_cfg sc7280_dsc[] = {
 	{
@@ -247,6 +255,8 @@ const struct dpu_mdss_cfg dpu_sc7280_cfg = {
 	.mixer = sc7280_lm,
 	.pingpong_count = ARRAY_SIZE(sc7280_pp),
 	.pingpong = sc7280_pp,
+	.merge_3d_count = ARRAY_SIZE(sc7280_merge_3d),
+	.merge_3d = sc7280_merge_3d,
 	.dsc_count = ARRAY_SIZE(sc7280_dsc),
 	.dsc = sc7280_dsc,
 	.wb_count = ARRAY_SIZE(sc7280_wb),

---
base-commit: efb26a23ed5f5dc3554886ab398f559dcb1de96b
change-id: 20251231-4k-969b53d2ea4c

Best regards,
-- 
Mahadevan P <mahadevan.p@oss.qualcomm.com>

On Thu, 01 Jan 2026 10:34:38 +0530, Mahadevan P wrote:
> On SC7280 targets, display modes with a width greater than the
> max_mixer_width (2400) are rejected during mode validation when
> merge3d is disabled. This limitation exists because, without a
> 3D merge block, two layer mixers cannot be combined(non-DSC interface),
> preventing large layers from being split across mixers. As a result,
> higher resolution modes cannot be supported.
> 
> [...]

Applied to msm-next, thanks!

[1/1] drm/msm/disp/dpu: add merge3d support for sc7280
      https://gitlab.freedesktop.org/lumag/msm/-/commit/2892de3f4f98

Best regards,
-- 
With best wishes
Dmitry

On Thu, Jan 01, 2026 at 10:34:38AM +0530, Mahadevan P wrote:
> On SC7280 targets, display modes with a width greater than the
> max_mixer_width (2400) are rejected during mode validation when
> merge3d is disabled. This limitation exists because, without a
> 3D merge block, two layer mixers cannot be combined(non-DSC interface),
> preventing large layers from being split across mixers. As a result,
> higher resolution modes cannot be supported.
> 
> Enable merge3d support on SC7280 to allow combining streams from
> two layer mixers into a single non-DSC interface. This capability
> removes the width restriction and enables buffer sizes beyond the
> 2400-pixel limit.
> 
> Fixes: 591e34a091d1 ("drm/msm/disp/dpu1: add support for display for SC7280 target")
> Signed-off-by: Mahadevan P <mahadevan.p@oss.qualcomm.com>
> ---
> Changes in v2:
>   - Updated commit message for clarity (Dmitry).
> ---
>  drivers/gpu/drm/msm/disp/dpu1/catalog/dpu_7_2_sc7280.h | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>


-- 
With best wishes
Dmitry