[Intel-gfx] [PATCH 2/9] drm/i915/display: Store compressed bpp in U6.4 format

Kandpal, Suraj suraj.kandpal at intel.com
Thu Aug 24 16:18:13 UTC 2023


> Subject: [Intel-gfx] [PATCH 2/9] drm/i915/display: Store compressed bpp in
> U6.4 format
> 
> DSC parameter bits_per_pixel is stored in U6.4 format.
> The 4 bits represent the fractional part of the bpp.
> Currently we use compressed_bpp member of dsc structure to store only the
> integral part of the bits_per_pixel.
> To store the full bits_per_pixel along with the fractional part, compressed_bpp
> is changed to store bpp in U6.4 formats. Intergral part is retrieved by simply
> right shifting the member compressed_bpp by 4.
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> ---
>  drivers/gpu/drm/i915/display/icl_dsi.c        | 10 ++++-----
>  drivers/gpu/drm/i915/display/intel_audio.c    |  2 +-
>  drivers/gpu/drm/i915/display/intel_bios.c     |  2 +-
>  .../drm/i915/display/intel_display_types.h    | 16 +++++++++++++-
>  drivers/gpu/drm/i915/display/intel_dp.c       | 21 +++++++++++--------
>  drivers/gpu/drm/i915/display/intel_vdsc.c     |  4 ++--
>  6 files changed, 36 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c
> b/drivers/gpu/drm/i915/display/icl_dsi.c
> index ad6488e9c2b2..81b8e97e9435 100644
> --- a/drivers/gpu/drm/i915/display/icl_dsi.c
> +++ b/drivers/gpu/drm/i915/display/icl_dsi.c
> @@ -330,7 +330,7 @@ static int afe_clk(struct intel_encoder *encoder,
>  	int bpp;
> 
>  	if (crtc_state->dsc.compression_enable)
> -		bpp = crtc_state->dsc.compressed_bpp;
> +		bpp = dsc_integral_compressed_bpp(crtc_state-
> >dsc.compressed_bpp);
>  	else
>  		bpp = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);
> 
> @@ -860,7 +860,7 @@ gen11_dsi_set_transcoder_timings(struct
> intel_encoder *encoder,
>  	 * compressed and non-compressed bpp.
>  	 */
>  	if (crtc_state->dsc.compression_enable) {
> -		mul = crtc_state->dsc.compressed_bpp;
> +		mul = dsc_integral_compressed_bpp(crtc_state-
> >dsc.compressed_bpp);
>  		div = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);
>  	}
> 
> @@ -884,7 +884,7 @@ gen11_dsi_set_transcoder_timings(struct
> intel_encoder *encoder,
>  		int bpp, line_time_us, byte_clk_period_ns;
> 
>  		if (crtc_state->dsc.compression_enable)
> -			bpp = crtc_state->dsc.compressed_bpp;
> +			bpp = dsc_integral_compressed_bpp(crtc_state-
> >dsc.compressed_bpp);
>  		else
>  			bpp = mipi_dsi_pixel_format_to_bpp(intel_dsi-
> >pixel_format);
> 
> @@ -1451,8 +1451,8 @@ static void gen11_dsi_get_timings(struct
> intel_encoder *encoder,
>  	struct drm_display_mode *adjusted_mode =
>  					&pipe_config->hw.adjusted_mode;
> 
> -	if (pipe_config->dsc.compressed_bpp) {
> -		int div = pipe_config->dsc.compressed_bpp;
> +	if (dsc_integral_compressed_bpp(pipe_config-
> >dsc.compressed_bpp)) {

Doesn't make sense to have this function to be called here this just
checks if we have compressed_bpp available or not extracting the
integral part should not be necessary

> +		int div =
> +dsc_integral_compressed_bpp(pipe_config->dsc.compressed_bpp);
>  		int mul = mipi_dsi_pixel_format_to_bpp(intel_dsi-
> >pixel_format);
> 
>  		adjusted_mode->crtc_htotal =
> diff --git a/drivers/gpu/drm/i915/display/intel_audio.c
> b/drivers/gpu/drm/i915/display/intel_audio.c
> index 3d9c9b4f27f8..93969b63cdd8 100644
> --- a/drivers/gpu/drm/i915/display/intel_audio.c
> +++ b/drivers/gpu/drm/i915/display/intel_audio.c
> @@ -528,7 +528,7 @@ static unsigned int calc_hblank_early_prog(struct
> intel_encoder *encoder,
>  	h_active = crtc_state->hw.adjusted_mode.crtc_hdisplay;
>  	h_total = crtc_state->hw.adjusted_mode.crtc_htotal;
>  	pixel_clk = crtc_state->hw.adjusted_mode.crtc_clock;
> -	vdsc_bpp = crtc_state->dsc.compressed_bpp;
> +	vdsc_bpp =
> +dsc_integral_compressed_bpp(crtc_state->dsc.compressed_bpp);
>  	cdclk = i915->display.cdclk.hw.cdclk;
>  	/* fec= 0.972261, using rounding multiplier of 1000000 */
>  	fec_coeff = 972261;
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c
> b/drivers/gpu/drm/i915/display/intel_bios.c
> index 858c959f7bab..fe1e376c4ba7 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.c
> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> @@ -3385,7 +3385,7 @@ static void fill_dsc(struct intel_crtc_state
> *crtc_state,
>  	crtc_state->pipe_bpp = bpc * 3;
> 
>  	crtc_state->dsc.compressed_bpp = min(crtc_state->pipe_bpp,
> -					     VBT_DSC_MAX_BPP(dsc-
> >max_bpp));
> +					     VBT_DSC_MAX_BPP(dsc-
> >max_bpp)) << 4;
> 
>  	/*
>  	 * FIXME: This is ugly, and slice count should take DSC engine diff --git
> a/drivers/gpu/drm/i915/display/intel_display_types.h
> b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 731f2ec04d5c..f749dc4e70df 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1353,7 +1353,7 @@ struct intel_crtc_state {
>  	struct {
>  		bool compression_enable;
>  		bool dsc_split;
> -		u16 compressed_bpp;
> +		u16 compressed_bpp; /* U6.4 format (first 4 bits for
> fractional part)
> +*/
>  		u8 slice_count;
>  		struct drm_dsc_config config;
>  	} dsc;
> @@ -2108,4 +2108,18 @@ to_intel_frontbuffer(struct drm_framebuffer *fb)
>  	return fb ? to_intel_framebuffer(fb)->frontbuffer : NULL;  }
> 
> +/* Returns integral part of the compressed bpp given in U6.4 format */
> +static inline int
> +dsc_integral_compressed_bpp(u16 compressed_bpp) {
> +	return compressed_bpp >> 4;
> +}

Maybe we can have two macro/functions that can be used to shift the fractional part for bpp
dsc_bpp_x_to_x16 and dsc_bpp_x16_to_x this can be used at a lot of places to avoid confusions everywhere
when and why we are shifting  by 4.
We can keep the dsc_fractional_compressed_bpp.

> +
> +/* Returns fractional part of the compressed bpp given in U6.4 format
> +*/ static inline int
> +dsc_fractional_compressed_bpp(u16 compressed_bpp) {
> +	return ((compressed_bpp & 0xF) * 10000 / 16); }
> +

Maybe dsc_get_fractional_bpp () ?

>  #endif /*  __INTEL_DISPLAY_TYPES_H__ */ diff --git
> a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 5b48bfe09d0e..32d0bee11f53 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1901,7 +1901,7 @@ xelpd_dsc_compute_link_config(struct intel_dp
> *intel_dp,
>  					      compressed_bpp,
>  					      timeslots);
>  		if (ret == 0) {
> -			pipe_config->dsc.compressed_bpp =
> compressed_bpp;
> +			pipe_config->dsc.compressed_bpp =
> compressed_bpp << 4;
>  			return 0;
>  		}
>  	}
> @@ -2171,17 +2171,19 @@ int intel_dp_dsc_compute_config(struct
> intel_dp *intel_dp,
>  	if (ret < 0) {
>  		drm_dbg_kms(&dev_priv->drm,
>  			    "Cannot compute valid DSC parameters for Input
> Bpp = %d "
> -			    "Compressed BPP = %d\n",
> +			    "Compressed BPP = %d.%d\n",
>  			    pipe_config->pipe_bpp,
> -			    pipe_config->dsc.compressed_bpp);
> +			    dsc_integral_compressed_bpp(pipe_config-
> >dsc.compressed_bpp),
> +			    dsc_fractional_compressed_bpp(pipe_config-
> >dsc.compressed_bpp));
>  		return ret;
>  	}
> 
>  	pipe_config->dsc.compression_enable = true;
>  	drm_dbg_kms(&dev_priv->drm, "DP DSC computed with Input Bpp =
> %d "
> -		    "Compressed Bpp = %d Slice Count = %d\n",
> +		    "Compressed Bpp = %d.%d Slice Count = %d\n",
>  		    pipe_config->pipe_bpp,
> -		    pipe_config->dsc.compressed_bpp,
> +		    dsc_integral_compressed_bpp(pipe_config-
> >dsc.compressed_bpp),
> +		    dsc_fractional_compressed_bpp(pipe_config-
> >dsc.compressed_bpp),
>  		    pipe_config->dsc.slice_count);
> 
>  	return 0;
> @@ -2260,15 +2262,16 @@ intel_dp_compute_link_config(struct
> intel_encoder *encoder,
> 
>  	if (pipe_config->dsc.compression_enable) {
>  		drm_dbg_kms(&i915->drm,
> -			    "DP lane count %d clock %d Input bpp %d
> Compressed bpp %d\n",
> +			    "DP lane count %d clock %d Input bpp %d
> Compressed bpp %d.%d\n",
>  			    pipe_config->lane_count, pipe_config->port_clock,
>  			    pipe_config->pipe_bpp,
> -			    pipe_config->dsc.compressed_bpp);
> +			    dsc_integral_compressed_bpp(pipe_config-
> >dsc.compressed_bpp),
> +			    dsc_fractional_compressed_bpp(pipe_config-
> >dsc.compressed_bpp));
> 
>  		drm_dbg_kms(&i915->drm,
>  			    "DP link rate required %i available %i\n",
>  			    intel_dp_link_required(adjusted_mode->crtc_clock,
> -						   pipe_config-
> >dsc.compressed_bpp),
> +
> dsc_integral_compressed_bpp(pipe_config->dsc.compressed_bpp)),
>  			    intel_dp_max_data_rate(pipe_config->port_clock,
>  						   pipe_config->lane_count));
>  	} else {
> @@ -2700,7 +2703,7 @@ intel_dp_compute_config(struct intel_encoder
> *encoder,
>  		intel_dp_limited_color_range(pipe_config, conn_state);
> 
>  	if (pipe_config->dsc.compression_enable)
> -		link_bpp = pipe_config->dsc.compressed_bpp;
> +		link_bpp =
> +dsc_integral_compressed_bpp(pipe_config->dsc.compressed_bpp);
>  	else
>  		link_bpp = intel_dp_output_bpp(pipe_config-
> >output_format,
>  					       pipe_config->pipe_bpp);
> diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c
> b/drivers/gpu/drm/i915/display/intel_vdsc.c
> index e4c395b4dc46..2dc6ea82c024 100644
> --- a/drivers/gpu/drm/i915/display/intel_vdsc.c
> +++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
> @@ -248,7 +248,7 @@ int intel_dsc_compute_params(struct intel_crtc_state
> *pipe_config)
>  	struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
>  	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
>  	struct drm_dsc_config *vdsc_cfg = &pipe_config->dsc.config;
> -	u16 compressed_bpp = pipe_config->dsc.compressed_bpp;
> +	u16 compressed_bpp =
> +dsc_integral_compressed_bpp(pipe_config->dsc.compressed_bpp);
>  	int err;
>  	int ret;
> 
> @@ -1040,7 +1040,7 @@ void intel_dsc_get_config(struct intel_crtc_state
> *crtc_state)
>  	if (pps0 & DSC_NATIVE_420_ENABLE)
>  		vdsc_cfg->bits_per_pixel >>= 1;
> 
> -	crtc_state->dsc.compressed_bpp = vdsc_cfg->bits_per_pixel >> 4;
> +	crtc_state->dsc.compressed_bpp = vdsc_cfg->bits_per_pixel;
>  out:
>  	intel_display_power_put(dev_priv, power_domain, wakeref);  }
> --
> 2.40.1



More information about the Intel-gfx mailing list