Re: [PATCH v4 4/4] drm/msm/dpu: fix SSPP_UBWC_STATIC_CTRL programming on UBWC 5.x+

From: Konrad Dybcio

Date: Mon Jan 19 2026 - 07:25:04 EST


On 1/19/26 1:16 PM, Dmitry Baryshkov wrote:
> 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.
>
> Fixes: c2577fc1740d ("drm/msm/dpu: Add support for SM8750")
> Tested-by: Val Packett <val@xxxxxxxxxxxx> # x1e80100-dell-latitude-7455
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
> ---

[...]

> + if (ctx->ubwc->ubwc_enc_version == UBWC_1_0) {
> fast_clear = fmt->alpha_enable ? BIT(31) : 0;
> - DPU_REG_WRITE(c, ubwc_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_ctrl_off,
> - fast_clear | (ctx->ubwc->ubwc_swizzle) |
> - (hbb << 4));
> - break;
> - case UBWC_3_0:
> - DPU_REG_WRITE(c, ubwc_ctrl_off,
> - BIT(30) | (ctx->ubwc->ubwc_swizzle) |
> - (hbb << 4));
> - break;
> - case UBWC_4_0:
> - DPU_REG_WRITE(c, ubwc_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);

This is pre-existing, but BIT(30) is not unconditional in SDE for v3

For this patch

Reviewed-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>

Konrad