Re: [PATCH 2/3] drm/dsc: Add native 420 and 422 support to compute_rc_params

[Manasi Navare via amd-gfx <amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>]

On Wed, Feb 13, 2019 at 09:45:35AM -0500, David Francis wrote:
> Native 420 and 422 transfer modes are new in DSC1.2
> 
> In these modes, each two pixels of a slice are treated as one
> pixel, so the slice width is half as large (round down) for
> the purposes of calucating the groups per line and chunk size
> in bytes
> 
> In native 422 mode, each pixel has four components, so the
> mux component of a group is larger by one additional mux word
> and one additional component
> 
> Now that there is native 422 support, the configuration option
> previously called enable422 is renamed to simple_422 to avoid
> confusion
> 
> Signed-off-by: David Francis <David.Francis@amd.com>

This looks good and verified that the DSC 1.2 spec actually renames it
as simple_422.

Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>

Manasi

> ---
>  drivers/gpu/drm/drm_dsc.c         | 31 +++++++++++++++++++++++--------
>  drivers/gpu/drm/i915/intel_vdsc.c |  4 ++--
>  include/drm/drm_dsc.h             |  4 ++--
>  3 files changed, 27 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_dsc.c b/drivers/gpu/drm/drm_dsc.c
> index 4b0e3c9c3ff8..9e675dd39a44 100644
> --- a/drivers/gpu/drm/drm_dsc.c
> +++ b/drivers/gpu/drm/drm_dsc.c
> @@ -77,7 +77,7 @@ void drm_dsc_pps_infoframe_pack(struct drm_dsc_pps_infoframe *pps_sdp,
>  		((dsc_cfg->bits_per_pixel & DSC_PPS_BPP_HIGH_MASK) >>
>  		 DSC_PPS_MSB_SHIFT) |
>  		dsc_cfg->vbr_enable << DSC_PPS_VBR_EN_SHIFT |
> -		dsc_cfg->enable422 << DSC_PPS_SIMPLE422_SHIFT |
> +		dsc_cfg->simple_422 << DSC_PPS_SIMPLE422_SHIFT |
>  		dsc_cfg->convert_rgb << DSC_PPS_CONVERT_RGB_SHIFT |
>  		dsc_cfg->block_pred_enable << DSC_PPS_BLOCK_PRED_EN_SHIFT;
>  
> @@ -246,19 +246,34 @@ int drm_dsc_compute_rc_parameters(struct drm_dsc_config *vdsc_cfg)
>  	unsigned long final_scale = 0;
>  	unsigned long rbs_min = 0;
>  
> -	/* Number of groups used to code each line of a slice */
> -	groups_per_line = DIV_ROUND_UP(vdsc_cfg->slice_width,
> -				       DSC_RC_PIXELS_PER_GROUP);
> +	if (vdsc_cfg->native_420 || vdsc_cfg->native_422) {
> +		/* Number of groups used to code each line of a slice */
> +		groups_per_line = DIV_ROUND_UP(vdsc_cfg->slice_width / 2,
> +					       DSC_RC_PIXELS_PER_GROUP);
>  
> -	/* chunksize in Bytes */
> -	vdsc_cfg->slice_chunk_size = DIV_ROUND_UP(vdsc_cfg->slice_width *
> -						  vdsc_cfg->bits_per_pixel,
> -						  (8 * 16));
> +		/* chunksize in Bytes */
> +		vdsc_cfg->slice_chunk_size = DIV_ROUND_UP(vdsc_cfg->slice_width / 2 *
> +							  vdsc_cfg->bits_per_pixel,
> +							  (8 * 16));
> +	} else {
> +		/* Number of groups used to code each line of a slice */
> +		groups_per_line = DIV_ROUND_UP(vdsc_cfg->slice_width,
> +					       DSC_RC_PIXELS_PER_GROUP);
> +
> +		/* chunksize in Bytes */
> +		vdsc_cfg->slice_chunk_size = DIV_ROUND_UP(vdsc_cfg->slice_width *
> +							  vdsc_cfg->bits_per_pixel,
> +							  (8 * 16));
> +	}
>  
>  	if (vdsc_cfg->convert_rgb)
>  		num_extra_mux_bits = 3 * (vdsc_cfg->mux_word_size +
>  					  (4 * vdsc_cfg->bits_per_component + 4)
>  					  - 2);
> +	else if (vdsc_cfg->native_422)
> +		num_extra_mux_bits = 4 * vdsc_cfg->mux_word_size +
> +			(4 * vdsc_cfg->bits_per_component + 4) +
> +			3 * (4 * vdsc_cfg->bits_per_component) - 2;
>  	else
>  		num_extra_mux_bits = 3 * vdsc_cfg->mux_word_size +
>  			(4 * vdsc_cfg->bits_per_component + 4) +
> diff --git a/drivers/gpu/drm/i915/intel_vdsc.c b/drivers/gpu/drm/i915/intel_vdsc.c
> index c76cec8bfb74..7702c5c8b3f2 100644
> --- a/drivers/gpu/drm/i915/intel_vdsc.c
> +++ b/drivers/gpu/drm/i915/intel_vdsc.c
> @@ -369,7 +369,7 @@ int intel_dp_compute_dsc_params(struct intel_dp *intel_dp,
>  			DSC_1_1_MAX_LINEBUF_DEPTH_BITS : line_buf_depth;
>  
>  	/* Gen 11 does not support YCbCr */
> -	vdsc_cfg->enable422 = false;
> +	vdsc_cfg->simple_422 = false;
>  	/* Gen 11 does not support VBR */
>  	vdsc_cfg->vbr_enable = false;
>  	vdsc_cfg->block_pred_enable =
> @@ -496,7 +496,7 @@ static void intel_configure_pps_for_dsc_encoder(struct intel_encoder *encoder,
>  		pps_val |= DSC_BLOCK_PREDICTION;
>  	if (vdsc_cfg->convert_rgb)
>  		pps_val |= DSC_COLOR_SPACE_CONVERSION;
> -	if (vdsc_cfg->enable422)
> +	if (vdsc_cfg->simple_422)
>  		pps_val |= DSC_422_ENABLE;
>  	if (vdsc_cfg->vbr_enable)
>  		pps_val |= DSC_VBR_ENABLE;
> diff --git a/include/drm/drm_dsc.h b/include/drm/drm_dsc.h
> index ad43494f1cc8..4e55e37943d7 100644
> --- a/include/drm/drm_dsc.h
> +++ b/include/drm/drm_dsc.h
> @@ -70,10 +70,10 @@ struct drm_dsc_config {
>  	/* Slice Height */
>  	u16 slice_height;
>  	/*
> -	 * 4:2:2 enable mode (from PPS, 4:2:2 conversion happens
> +	 * Simple 4:2:2 mode (from PPS, 4:2:2 conversion happens
>  	 * outside of DSC encode/decode algorithm)
>  	 */
> -	bool enable422;
> +	bool simple_422;
>  	/* Picture Width */
>  	u16 pic_width;
>  	/* Picture Height */
> -- 
> 2.17.1
> 
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