Re: [PATCH v2 5/6] drm/msm/dsi: support DSC configurations with slice_per_pkt > 1

Jessica Zhang
2023-12-07T20:29:23Z

On 11/14/2023 2:58 PM, Jonathan Marek wrote:
> Add a dsc_slice_per_pkt field to mipi_dsi_device struct and the necessary
> changes to msm driver to support this field.
>
> Note that the removed "pkt_per_line = slice_per_intf * slice_per_pkt"
> comment is incorrect.

Hi John,

Thanks for catching the typo.

>
> Signed-off-by: Jonathan Marek <jonathan@marek.ca>
> ---
> drivers/gpu/drm/msm/dsi/dsi_host.c | 25 ++++++++++---------------
> include/drm/drm_mipi_dsi.h | 1 +
> 2 files changed, 11 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 842765063b1b..892a463a7e03 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -161,6 +161,7 @@ struct msm_dsi_host {
>
> struct drm_display_mode *mode;
> struct drm_dsc_config *dsc;
> + unsigned int dsc_slice_per_pkt;
>
> /* connected device info */
> unsigned int channel;
> @@ -857,17 +858,10 @@ static void dsi_update_dsc_timing(struct msm_dsi_host *msm_host, bool is_cmd_mod
> slice_per_intf = msm_dsc_get_slices_per_intf(dsc, hdisplay);
>
> total_bytes_per_intf = dsc->slice_chunk_size * slice_per_intf;
> - bytes_per_pkt = dsc->slice_chunk_size; /* * slice_per_pkt; */
> + bytes_per_pkt = dsc->slice_chunk_size * msm_host->dsc_slice_per_pkt;
>
> eol_byte_num = total_bytes_per_intf % 3;
> -
> - /*
> - * Typically, pkt_per_line = slice_per_intf * slice_per_pkt.
> - *
> - * Since the current driver only supports slice_per_pkt = 1,
> - * pkt_per_line will be equal to slice per intf for now.
> - */
> - pkt_per_line = slice_per_intf;
> + pkt_per_line = slice_per_intf / msm_host->dsc_slice_per_pkt;
>
> if (is_cmd_mode) /* packet data type */
> reg = DSI_COMMAND_COMPRESSION_MODE_CTRL_STREAM0_DATATYPE(MIPI_DSI_DCS_LONG_WRITE);
> @@ -1004,12 +998,8 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
> else
> /*
> * When DSC is enabled, WC = slice_chunk_size * slice_per_pkt + 1.
> - * Currently, the driver only supports default value of slice_per_pkt = 1
> - *
> - * TODO: Expand mipi_dsi_device struct to hold slice_per_pkt info
> - * and adjust DSC math to account for slice_per_pkt.
> */
> - wc = msm_host->dsc->slice_chunk_size + 1;
> + wc = msm_host->dsc->slice_chunk_size * msm_host->dsc_slice_per_pkt + 1;

Maybe we can reuse bytes_per_pkt here.

>
> dsi_write(msm_host, REG_DSI_CMD_MDP_STREAM0_CTRL,
> DSI_CMD_MDP_STREAM0_CTRL_WORD_COUNT(wc) |
> @@ -1636,8 +1626,13 @@ 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;
> + msm_host->dsc_slice_per_pkt = dsi->dsc_slice_per_pkt;
> + /* for backwards compatibility, assume 1 if not set */
> + if (!msm_host->dsc_slice_per_pkt)
> + msm_host->dsc_slice_per_pkt = 1;
> + }
>
> /* Some gpios defined in panel DT need to be controlled by host */
> ret = dsi_host_init_panel_gpios(msm_host, &dsi->dev);
> diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
> index c9df0407980c..3e32fa52d94b 100644
> --- a/include/drm/drm_mipi_dsi.h
> +++ b/include/drm/drm_mipi_dsi.h
> @@ -193,6 +193,7 @@ struct mipi_dsi_device {
> unsigned long hs_rate;
> unsigned long lp_rate;
> struct drm_dsc_config *dsc;

Any reason for not putting this in drm_dsc_config?

Thanks,

Jessica Zhang

> + unsigned int dsc_slice_per_pkt;
> };
>
> #define MIPI_DSI_MODULE_PREFIX "mipi-dsi:"
> --
> 2.26.1
>