> Subject: [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@xxxxxxxxx>
> ---
> 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
