linux-kernel - [PATCH 4/4] drm/msm/dpu: fix SSPP_UBWC_STATIC

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Message-Id: <20260117-msm-ubwc-fixes-v1-4-d5c65ea552c7@oss.qualcomm.com>
Date: Sat, 17 Jan 2026 08:35:57 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Rob Clark <robin.clark@....qualcomm.com>,
        Dmitry Baryshkov <lumag@...nel.org>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Jessica Zhang <jesszhan0024@...il.com>, Sean Paul <sean@...rly.run>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Konrad Dybcio <konrad.dybcio@....qualcomm.com>,
        Konrad Dybcio <konradybcio@...nel.org>, Vinod Koul <vkoul@...nel.org>,
        Stephan Gerhold <stephan.gerhold@...aro.org>
Cc: linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH 4/4] drm/msm/dpu: fix SSPP_UBWC_STATIC_CTRL programming on
 UBWC 5.x+

Code in dpu_hw_sspp_setup_format() doesn't handle UBWC versions bigger
than 4.0. Replace switch-case with if-else checks, making sure that the
register is initialized on UBWC 5.x (and later) hosts.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_sspp.c | 41 ++++++++++++++---------------
 1 file changed, 20 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_sspp.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_sspp.c
index a99e33230514..b0c97f5e47ea 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_sspp.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_sspp.c
@@ -279,6 +279,7 @@ static void dpu_hw_sspp_setup_format(struct dpu_sw_pipe *pipe,
 
 	if (fmt->fetch_mode != MDP_FETCH_LINEAR) {
 		u32 hbb = ctx->ubwc->highest_bank_bit - 13;
+		u32 ctrl_val;
 
 		if (MSM_FORMAT_IS_UBWC(fmt))
 			opmode |= MDSS_MDP_OP_BWC_EN;
@@ -286,30 +287,28 @@ static void dpu_hw_sspp_setup_format(struct dpu_sw_pipe *pipe,
 		DPU_REG_WRITE(c, SSPP_FETCH_CONFIG,
 			DPU_FETCH_CONFIG_RESET_VALUE |
 			hbb << 18);
-		switch (ctx->ubwc->ubwc_enc_version) {
-		case UBWC_1_0:
+
+		if (ctx->ubwc->ubwc_enc_version == UBWC_1_0) {
 			fast_clear = fmt->alpha_enable ? BIT(31) : 0;
-			DPU_REG_WRITE(c, ubwc_static_ctrl_off,
-					fast_clear | (ctx->ubwc->ubwc_swizzle & 0x1) |
-					BIT(8) |
-					(hbb << 4));
-			break;
-		case UBWC_2_0:
+			ctrl_val = fast_clear | (ctx->ubwc->ubwc_swizzle & 0x1) |
+				BIT(8) | (hbb << 4);
+		} else if (ctx->ubwc->ubwc_enc_version == UBWC_2_0) {
 			fast_clear = fmt->alpha_enable ? BIT(31) : 0;
-			DPU_REG_WRITE(c, ubwc_static_ctrl_off,
-					fast_clear | (ctx->ubwc->ubwc_swizzle) |
-					(hbb << 4));
-			break;
-		case UBWC_3_0:
-			DPU_REG_WRITE(c, ubwc_static_ctrl_off,
-					BIT(30) | (ctx->ubwc->ubwc_swizzle) |
-					(hbb << 4));
-			break;
-		case UBWC_4_0:
-			DPU_REG_WRITE(c, ubwc_static_ctrl_off,
-					MSM_FORMAT_IS_YUV(fmt) ? 0 : BIT(30));
-			break;
+			ctrl_val = fast_clear | ctx->ubwc->ubwc_swizzle | (hbb << 4);
+		} else if (ctx->ubwc->ubwc_enc_version == UBWC_3_0) {
+			ctrl_val = BIT(30) | (ctx->ubwc->ubwc_swizzle) | (hbb << 4);
+		} else if (ctx->ubwc->ubwc_enc_version == UBWC_4_0) {
+			ctrl_val = MSM_FORMAT_IS_YUV(fmt) ? 0 : BIT(30);
+		} else { /* UBWC 5.0+ */
+			if (MSM_FORMAT_IS_YUV(fmt))
+				ctrl_val = 0;
+			else if (MSM_FORMAT_IS_DX(fmt)) /* or FP16, but it's unsupported */
+				ctrl_val = BIT(30);
+			else
+				ctrl_val = BIT(30) | BIT(31);
 		}
+
+		DPU_REG_WRITE(c, ubwc_static_ctrl_off, ctrl_val);
 	}
 
 	opmode |= MDSS_MDP_OP_PE_OVERRIDE;

-- 
2.47.3