On Mon, Jul 27, 2026 at 04:08:41PM +0800, Jun Nie wrote:
> Some panels require multiple slice to be sent in a single DSC packet. And
> this feature is a must for specific panels, such as Sharp ls026b3sa06. Add
> a dsc_slice_per_pkt member into struct drm_dsc_config and support the
> feature in msm mdss driver.
>
> Co-developed-by: Jonathan Marek <[email protected]>
> Signed-off-by: Jonathan Marek <[email protected]>
> Signed-off-by: Jun Nie <[email protected]>
> ---
> drivers/gpu/drm/msm/dsi/dsi_host.c | 27 ++++++++++++---------------
> include/drm/display/drm_dsc.h | 7 +++++++
> 2 files changed, 19 insertions(+), 15 deletions(-)
>
> @@ -1719,8 +1709,14 @@ static int dsi_host_attach(struct mipi_dsi_host *host,
> msm_host->lanes = dsi->lanes;
> msm_host->format = dsi->format;
> msm_host->mode_flags = dsi->mode_flags;
> - if (dsi->dsc)
> + if (dsi->dsc) {
> msm_host->dsc = dsi->dsc;
> + /* for backwards compatibility, assume 1 if not set */
> + msm_host->dsc_slice_per_pkt = dsi->dsc->dsc_slice_per_pkt ?: 1;
> + } else {
> + msm_host->dsc = NULL;
> + msm_host->dsc_slice_per_pkt = 0;
> + }
Why do you need the else branch? Isn't it already NULL / 0 by default?
>
> if (msm_host->format == MIPI_DSI_FMT_RGB101010) {
> if (!msm_dsi_host_version_geq(msm_host, MSM_DSI_VER_MAJOR_6G,
> @@ -1757,6 +1753,7 @@ static int dsi_host_detach(struct mipi_dsi_host *host,
> struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
>
> dsi_dev_detach(msm_host->pdev);
> + msm_host->dsc = NULL;
If you are fixing something, it should come as a separate commit.
>
> DBG("id=%d", msm_host->id);
>
> diff --git a/include/drm/display/drm_dsc.h b/include/drm/display/drm_dsc.h
> index bbbe7438473d3..c522ab3d71853 100644
> --- a/include/drm/display/drm_dsc.h
> +++ b/include/drm/display/drm_dsc.h
> @@ -267,6 +267,13 @@ struct drm_dsc_config {
> * Offset adjustment for second line in Native 4:2:0 mode
> */
> u16 second_line_offset_adj;
> +
> + /**
> + * @dsc_slice_per_pkt:
> + * Number of DSC slices to be sent in a single packet. This is not
> + * part of DSC standard, and only used in some DSI panels so far.
> + */
> + unsigned int dsc_slice_per_pkt;
If it's not a part of the standard, I think, it should not be a part of
drm_dsc_config. In the end, drm_dsc_config is also being used by other
parties, e.g. DP or HDMI. A year ago I saw a version of this patch,
having this field in the struct mipi_dsi_device. I think it's a more
correct place.
--
With best wishes
Dmitry
