On Fri, Mar 06, 2026 at 05:25:53PM +0800, Pengyu Luo wrote:
> Using incorrect parameters does not seem to affect the display, but we
> should use the correct in accordance with the DSC 1.1 or 1.2.
>
> Signed-off-by: Pengyu Luo <[email protected]>
> ---
> drivers/gpu/drm/msm/dsi/dsi_host.c | 31 +++++++++++++++++++++++++++---
> 1 file changed, 28 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c
> b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index b60b26ddb0..276c63d2ac 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -1843,10 +1843,35 @@ static int dsi_populate_dsc_params(struct
> msm_dsi_host *msm_host, struct drm_dsc
> drm_dsc_set_const_params(dsc);
> drm_dsc_set_rc_buf_thresh(dsc);
>
> - /* DPU supports only pre-SCR panels */
> - ret = drm_dsc_setup_rc_params(dsc, DRM_DSC_1_1_PRE_SCR);
> + if (dsc->dsc_version_major != 1) {
> + DRM_DEV_ERROR(&msm_host->pdev->dev, "Unsupported DSC version:
> %x.%x\n",
> + dsc->dsc_version_major, dsc->dsc_version_minor);
> + return -EOPNOTSUPP;
> + }
> +
> + switch (dsc->dsc_version_minor) {
> + case 1:
> + /*
> + * For DSC1.1. the upstream lacks SCR parameters, the downstream
> + * parameters are unverified here, we support pre-SCR only.
It doesn't. It's the same as DRM_DSC_1_2_444. Please send a patch adding
the comment.
> + */
> + ret = drm_dsc_setup_rc_params(dsc, DRM_DSC_1_1_PRE_SCR);
> + break;
> + case 2:
> + if (dsc->native_422)
> + ret = drm_dsc_setup_rc_params(dsc, DRM_DSC_1_2_422);
> + else if (dsc->native_420)
> + ret = drm_dsc_setup_rc_params(dsc, DRM_DSC_1_2_420);
> + else
It's not that we support 422/420 output... But yes, it's easier to fix
it now.
> + ret = drm_dsc_setup_rc_params(dsc, DRM_DSC_1_2_444);
> + break;
> + default:
> + ret = -EOPNOTSUPP;
> + }
> +
> if (ret) {
> - DRM_DEV_ERROR(&msm_host->pdev->dev, "could not find DSC RC
> parameters\n");
> + DRM_DEV_ERROR(&msm_host->pdev->dev, "could not find DSC RC
> parameters for DSC version: %x.%x\n",
> + dsc->dsc_version_major, dsc->dsc_version_minor);
> return ret;
> }
>
> --
> 2.53.0
>
--
With best wishes
Dmitry
