drm/i915/dsc: Move rc param calculation for native_420

Move rc_param calculation for native_420 into calculate_rc_parameter.
second_line_bpg_offset and second_line_offset_adj are both rc params
and it would be better to have these calculated where all the other
rc parameters are calculated.

--v2
-Add the reason for commit in commit message [Jani]

--v3
-Move nsl_second_line_bpg_offset with the other 420 calculation
in calculate_rc_param [Ankit]

--v4
-Fix comment alignment [Ankit]

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230705051502.2568245-2-suraj.kandpal@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c b/drivers/gpu/drm/i915/display/intel_vdsc.c
index 530f3c0..6e2c392 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_vdsc.c
+++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
@@ -78,6 +78,28 @@ calculate_rc_params(struct drm_dsc_config *vdsc_cfg)
        else
                vdsc_cfg->first_line_bpg_offset = 2 * (vdsc_cfg->slice_height - 1);
 
+       /*
+        * According to DSC 1.2 spec in Section 4.1 if native_420 is set:
+        * -second_line_bpg_offset is 12 in general and equal to 2*(slice_height-1) if slice
+        * height < 8.
+        * -second_line_offset_adj is 512 as shown by emperical values to yield best chroma
+        * preservation in second line.
+        * -nsl_bpg_offset is calculated as second_line_offset/slice_height -1 then rounded
+        * up to 16 fractional bits, we left shift second line offset by 11 to preserve 11
+        * fractional bits.
+        */
+       if (vdsc_cfg->native_420) {
+               if (vdsc_cfg->slice_height >= 8)
+                       vdsc_cfg->second_line_bpg_offset = 12;
+               else
+                       vdsc_cfg->second_line_bpg_offset =
+                               2 * (vdsc_cfg->slice_height - 1);
+
+               vdsc_cfg->second_line_offset_adj = 512;
+               vdsc_cfg->nsl_bpg_offset = DIV_ROUND_UP(vdsc_cfg->second_line_bpg_offset << 11,
+                                                       vdsc_cfg->slice_height - 1);
+       }
+
        /* Our hw supports only 444 modes as of today */
        if (bpp >= 12)
                vdsc_cfg->initial_offset = 2048;
@@ -190,30 +212,12 @@ int intel_dsc_compute_params(struct intel_crtc_state *pipe_config)
        vdsc_cfg->bits_per_pixel = compressed_bpp << 4;
 
        /*
-        * According to DSC 1.2 specs in Section 4.1 if native_420 is set:
-        * -We need to double the current bpp.
-        * -second_line_bpg_offset is 12 in general and equal to 2*(slice_height-1) if slice
-        * height < 8.
-        * -second_line_offset_adj is 512 as shown by emperical values to yeild best chroma
-        * preservation in second line.
-        * -nsl_bpg_offset is calculated as second_line_offset/slice_height -1 then rounded
-        * up to 16 fractional bits, we left shift second line offset by 11 to preserve 11
-        * fractional bits.
+        * According to DSC 1.2 specs in Section 4.1 if native_420 is set
+        * we need to double the current bpp.
         */
-       if (vdsc_cfg->native_420) {
+       if (vdsc_cfg->native_420)
                vdsc_cfg->bits_per_pixel <<= 1;
 
-               if (vdsc_cfg->slice_height >= 8)
-                       vdsc_cfg->second_line_bpg_offset = 12;
-               else
-                       vdsc_cfg->second_line_bpg_offset =
-                               2 * (vdsc_cfg->slice_height - 1);
-
-               vdsc_cfg->second_line_offset_adj = 512;
-               vdsc_cfg->nsl_bpg_offset = DIV_ROUND_UP(vdsc_cfg->second_line_bpg_offset << 11,
-                                                       vdsc_cfg->slice_height - 1);
-       }
-
        vdsc_cfg->bits_per_component = pipe_config->pipe_bpp / 3;
 
        drm_dsc_set_rc_buf_thresh(vdsc_cfg);