On 2022-10-09 20:50:54, Marijn Suijten wrote:

Apologies.  After attempting to recover from an unexpected interruption
_right as I was sending this series_, this patch got sent twice as it
only later appeared to also have made its way through in the first round
[1], together with the cover letter and first five patches.

[1]: 
https://lore.kernel.org/linux-arm-msm/20221009184824.457416-7-marijn.suij...@somainline.org/

- Marijn

> As per the FIXME this code is entirely duplicate with what is already
> provided inside drm_dsc_compute_rc_parameters(), and it is yet unknown
> why this comment was put in place instead of resolved from the get-go.
> Not only does it save on duplication, it would have also spared certain
> issues.
> 
> For example, this code from downstream assumed dsc->bits_per_pixel to
> contain an integer value, whereas the upstream drm_dsc_config struct has
> it with 4 fractional bits.  drm_dsc_compute_rc_parameters() already
> accounts for this feat, and the sole remaining use of
> dsc->bits_per_pixel inside dsi_populate_dsc_params() will be addressed
> in a separate patch.
> 
> Fixes: b9080324d6ca ("drm/msm/dsi: add support for dsc data")
> Signed-off-by: Marijn Suijten <marijn.suij...@somainline.org>
> ---
>  drivers/gpu/drm/msm/dsi/dsi_host.c | 64 +++---------------------------
>  1 file changed, 6 insertions(+), 58 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c 
> b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 83cde4d62b68..68c39debc22f 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -21,6 +21,7 @@
>  
>  #include <video/mipi_display.h>
>  
> +#include <drm/display/drm_dsc_helper.h>
>  #include <drm/drm_of.h>
>  
>  #include "dsi.h"
> @@ -1771,14 +1772,6 @@ static char bpg_offset[DSC_NUM_BUF_RANGES] = {
>  
>  static int dsi_populate_dsc_params(struct drm_dsc_config *dsc)
>  {
> -     int mux_words_size;
> -     int groups_per_line, groups_total;
> -     int min_rate_buffer_size;
> -     int hrd_delay;
> -     int pre_num_extra_mux_bits, num_extra_mux_bits;
> -     int slice_bits;
> -     int data;
> -     int final_value, final_scale;
>       int i;
>  
>       dsc->rc_model_size = 8192;
> @@ -1804,11 +1797,11 @@ static int dsi_populate_dsc_params(struct 
> drm_dsc_config *dsc)
>       if (dsc->bits_per_pixel != 8)
>               dsc->initial_offset = 2048;     /* bpp = 12 */
>  
> -     mux_words_size = 48;            /* bpc == 8/10 */
> -     if (dsc->bits_per_component == 12)
> -             mux_words_size = 64;
> +     if (dsc->bits_per_component <= 10)
> +             dsc->mux_word_size = DSC_MUX_WORD_SIZE_8_10_BPC;
> +     else
> +             dsc->mux_word_size = DSC_MUX_WORD_SIZE_12_BPC;
>  
> -     dsc->mux_word_size = mux_words_size;
>       dsc->initial_xmit_delay = 512;
>       dsc->initial_scale_value = 32;
>       dsc->first_line_bpg_offset = 12;
> @@ -1820,52 +1813,7 @@ static int dsi_populate_dsc_params(struct 
> drm_dsc_config *dsc)
>       dsc->rc_quant_incr_limit0 = 11;
>       dsc->rc_quant_incr_limit1 = 11;
>  
> -     /* FIXME: need to call drm_dsc_compute_rc_parameters() so that rest of
> -      * params are calculated
> -      */
> -     groups_per_line = DIV_ROUND_UP(dsc->slice_width, 3);
> -     dsc->slice_chunk_size = DIV_ROUND_UP(dsc->slice_width * 
> dsc->bits_per_pixel, 8);
> -
> -     /* rbs-min */
> -     min_rate_buffer_size =  dsc->rc_model_size - dsc->initial_offset +
> -                             dsc->initial_xmit_delay * dsc->bits_per_pixel +
> -                             groups_per_line * dsc->first_line_bpg_offset;
> -
> -     hrd_delay = DIV_ROUND_UP(min_rate_buffer_size, dsc->bits_per_pixel);
> -
> -     dsc->initial_dec_delay = hrd_delay - dsc->initial_xmit_delay;
> -
> -     dsc->initial_scale_value = 8 * dsc->rc_model_size /
> -                                    (dsc->rc_model_size - 
> dsc->initial_offset);
> -
> -     slice_bits = 8 * dsc->slice_chunk_size * dsc->slice_height;
> -
> -     groups_total = groups_per_line * dsc->slice_height;
> -
> -     data = dsc->first_line_bpg_offset * 2048;
> -
> -     dsc->nfl_bpg_offset = DIV_ROUND_UP(data, (dsc->slice_height - 1));
> -
> -     pre_num_extra_mux_bits = 3 * (mux_words_size + (4 * 
> dsc->bits_per_component + 4) - 2);
> -
> -     num_extra_mux_bits = pre_num_extra_mux_bits - (mux_words_size -
> -                          ((slice_bits - pre_num_extra_mux_bits) % 
> mux_words_size));
> -
> -     data = 2048 * (dsc->rc_model_size - dsc->initial_offset + 
> num_extra_mux_bits);
> -     dsc->slice_bpg_offset = DIV_ROUND_UP(data, groups_total);
> -
> -     data = dsc->initial_xmit_delay * dsc->bits_per_pixel;
> -     final_value =  dsc->rc_model_size - data + num_extra_mux_bits;
> -     dsc->final_offset = final_value;
> -
> -     final_scale = 8 * dsc->rc_model_size / (dsc->rc_model_size - 
> final_value);
> -
> -     data = (final_scale - 9) * (dsc->nfl_bpg_offset + 
> dsc->slice_bpg_offset);
> -     dsc->scale_increment_interval = (2048 * dsc->final_offset) / data;
> -
> -     dsc->scale_decrement_interval = groups_per_line / 
> (dsc->initial_scale_value - 8);
> -
> -     return 0;
> +     return drm_dsc_compute_rc_parameters(dsc);
>  }
>  
>  static int dsi_host_parse_dt(struct msm_dsi_host *msm_host)
> -- 
> 2.38.0
> 

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