On 8/2/2023 4:45 PM, Kandpal, Suraj wrote:
1.1
This change is required for DSC 1.1 because the current calculation is for DSC
1.2 and may get a calculated value which is not recommended by DSC 1.1, for
example, the calculated value at 8bpp becomes 15, not the value of 12
recommened by DSC 1.1.
Cc: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
Cc: Juha-Pekka Heikkil <juha-pekka.heikkila@xxxxxxxxx>
Signed-off-by: William Tseng <william.tseng@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_vdsc.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c
b/drivers/gpu/drm/i915/display/intel_vdsc.c
index bd9116d2cd76..9b350f5f8ebb 100644
--- a/drivers/gpu/drm/i915/display/intel_vdsc.c
+++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
@@ -72,11 +72,18 @@ calculate_rc_params(struct drm_dsc_config
*vdsc_cfg)
int qp_bpc_modifier = (bpc - 8) * 2;
u32 res, buf_i, bpp_i;
- if (vdsc_cfg->slice_height >= 8)
- vdsc_cfg->first_line_bpg_offset =
- 12 + DIV_ROUND_UP((9 * min(34, vdsc_cfg-
This seem to be incorrect as per the spec this should have been
first_line_bpg_offset = 12 + floor(0.09 * MIN (34, slice_height – 8))for
slice_height ≥ 8
So instead of rounding up we should have just divided.
slice_height - 8)), 100);
- else
- vdsc_cfg->first_line_bpg_offset = 2 * (vdsc_cfg-
slice_height - 1);
+ if (vdsc_cfg->dsc_version_minor == 2) {
I think the check here should be for minor version 1 and move the code in this block to
the else block and vice versa as this 8 bpp corner case is applicable only to DSC 1.1
+ if (vdsc_cfg->slice_height >= 8)
+ vdsc_cfg->first_line_bpg_offset =
+ 12 + DIV_ROUND_UP((9 * min(34, vdsc_cfg-
slice_height - 8)), 100);
+ else
+ vdsc_cfg->first_line_bpg_offset = 2 * (vdsc_cfg-
slice_height - 1);
+ } else {
+ if (bpp == 8)
+ rc->first_line_bpg_offset = 12;
+ else
+ rc->first_line_bpg_offset = 15;
+ }
Add the section in DSC spec/ Cmodel from where one can verify this in comments
I think this is coming from the recommended/ required value from DSC 1.1.
Regards,
Ankit
Regards,
Suraj Kandpal
/* Our hw supports only 444 modes as of today */
if (bpp >= 12)
--
2.34.1
