Thank you for the comments. I have made the corresponding changes to the revised patch in version No.3.
-----Original Message----- From: Kandpal, Suraj <[email protected]> Sent: Wednesday, August 2, 2023 7:15 PM To: Tseng, William <[email protected]>; [email protected] Cc: Heikkila, Juha-pekka <[email protected]>; Tseng, William <[email protected]>; Nautiyal, Ankit K <[email protected]> Subject: RE: [Intel-gfx] [PATCH] drm/i915/xelpd: Calculate first_line_bpg_offset for DSC 1.1 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 <[email protected]> > Cc: Juha-Pekka Heikkil <[email protected]> > Signed-off-by: William Tseng <[email protected]> > --- > 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- > >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 Regards, Suraj Kandpal > > /* Our hw supports only 444 modes as of today */ > if (bpp >= 12) > -- > 2.34.1
