Re: [PATCH v2 1/6] drm/msm/dpu: fix video mode DSC for DSI

[Dmitry Baryshkov]

On Wed, 15 Nov 2023 at 01:00, Jonathan Marek <jonathan@xxxxxxxx> wrote:
>
> Add necessary DPU changes for DSC to work with DSI video mode.
>
> Note this changes the logic to enable HCTL to match downstream, it will
> now be enabled for the no-DSC no-widebus case.
>
> Signed-off-by: Jonathan Marek <jonathan@xxxxxxxx>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c         |  2 +-
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h    |  2 +-
>  .../gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c    | 11 +++++++++++
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c         | 13 ++++++++++++-
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h         |  1 +
>  5 files changed, 26 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index 1cf7ff6caff4..d745c8678b9d 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -2477,7 +2477,7 @@ enum dpu_intf_mode dpu_encoder_get_intf_mode(struct drm_encoder *encoder)
>         return INTF_MODE_NONE;
>  }
>
> -unsigned int dpu_encoder_helper_get_dsc(struct dpu_encoder_phys *phys_enc)
> +unsigned int dpu_encoder_helper_get_dsc(const struct dpu_encoder_phys *phys_enc)

Why?

>  {
>         struct drm_encoder *encoder = phys_enc->parent;
>         struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(encoder);
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
> index 6f04c3d56e77..7e27a7da0887 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
> @@ -332,7 +332,7 @@ static inline enum dpu_3d_blend_mode dpu_encoder_helper_get_3d_blend_mode(
>   *   used for this encoder.
>   * @phys_enc: Pointer to physical encoder structure
>   */
> -unsigned int dpu_encoder_helper_get_dsc(struct dpu_encoder_phys *phys_enc);
> +unsigned int dpu_encoder_helper_get_dsc(const struct dpu_encoder_phys *phys_enc);
>
>  /**
>   * dpu_encoder_helper_split_config - split display configuration helper function
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
> index a01fda711883..df10800a9615 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
> @@ -100,6 +100,8 @@ static void drm_mode_to_intf_timing_params(
>         }
>
>         timing->wide_bus_en = dpu_encoder_is_widebus_enabled(phys_enc->parent);
> +       if (dpu_encoder_helper_get_dsc(phys_enc))
> +               timing->compression_en = true;
>
>         /*
>          * for DP, divide the horizonal parameters by 2 when
> @@ -112,6 +114,15 @@ static void drm_mode_to_intf_timing_params(
>                 timing->h_front_porch = timing->h_front_porch >> 1;
>                 timing->hsync_pulse_width = timing->hsync_pulse_width >> 1;
>         }
> +
> +       /*
> +        * for DSI, if compression is enabled, then divide the horizonal active
> +        * timing parameters by compression ratio.
> +        */
> +       if (phys_enc->hw_intf->cap->type != INTF_DP && timing->compression_en) {
> +               timing->width = timing->width / 3; /* XXX: don't assume 3:1 compression ratio */

Is this /3 from bpp / compressed_bpp?

> +               timing->xres = timing->width;
> +       }
>  }
>
>  static u32 get_horizontal_total(const struct dpu_hw_intf_timing_params *timing)
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
> index e8b8908d3e12..d6fe45a6da2d 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
> @@ -166,10 +166,21 @@ static void dpu_hw_intf_setup_timing_engine(struct dpu_hw_intf *ctx,
>          * video timing. It is recommended to enable it for all cases, except
>          * if compression is enabled in 1 pixel per clock mode
>          */
> +       if (!p->compression_en || p->wide_bus_en)
> +               intf_cfg2 |= INTF_CFG2_DATA_HCTL_EN;
> +
>         if (p->wide_bus_en)
> -               intf_cfg2 |= INTF_CFG2_DATABUS_WIDEN | INTF_CFG2_DATA_HCTL_EN;
> +               intf_cfg2 |= INTF_CFG2_DATABUS_WIDEN;
>
>         data_width = p->width;
> +       if (p->wide_bus_en && !dp_intf)
> +               data_width = p->width >> 1;
> +
> +       if (p->compression_en)
> +               intf_cfg2 |= INTF_CFG2_DCE_DATA_COMPRESS;
> +
> +       if (p->compression_en && dp_intf)
> +               DPU_ERROR("missing adjustments for DSC+DP\n");
>
>         hsync_data_start_x = hsync_start_x;
>         hsync_data_end_x =  hsync_start_x + data_width - 1;

This should go into a separate commit with the proper justification.

> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h
> index c539025c418b..15a5fdadd0a0 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h
> @@ -33,6 +33,7 @@ struct dpu_hw_intf_timing_params {
>         u32 hsync_skew;
>
>         bool wide_bus_en;
> +       bool compression_en;
>  };
>
>  struct dpu_hw_intf_prog_fetch {
> --
> 2.26.1
>


-- 
With best wishes
Dmitry