> Subject: [PATCH 5/8] drm/i915/dsc/mtl: Add support for fractional bpp > > From: Vandita Kulkarni <[email protected]> > > Consider the fractional bpp while reading the qp values. > > v2: Use helpers for fractional, integral bits of bits_per_pixel. (Suraj) >
LGTM. Reviewed-by: Suraj Kandpal <[email protected]> > Signed-off-by: Vandita Kulkarni <[email protected]> > Signed-off-by: Ankit Nautiyal <[email protected]> > --- > .../gpu/drm/i915/display/intel_qp_tables.c | 3 --- > drivers/gpu/drm/i915/display/intel_vdsc.c | 25 +++++++++++++++---- > 2 files changed, 20 insertions(+), 8 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_qp_tables.c > b/drivers/gpu/drm/i915/display/intel_qp_tables.c > index 543cdc46aa1d..600c815e37e4 100644 > --- a/drivers/gpu/drm/i915/display/intel_qp_tables.c > +++ b/drivers/gpu/drm/i915/display/intel_qp_tables.c > @@ -34,9 +34,6 @@ > * These qp tables are as per the C model > * and it has the rows pointing to bpps which increment > * in steps of 0.5 > - * We do not support fractional bpps as of today, > - * hence we would skip the fractional bpps during > - * our references for qp calclulations. > */ > static const u8 > rc_range_minqp444_8bpc[DSC_NUM_BUF_RANGES][RC_RANGE_QP444_8BPC > _MAX_NUM_BPP] = { > { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, > diff --git > a/drivers/gpu/drm/i915/display/intel_vdsc.c > b/drivers/gpu/drm/i915/display/intel_vdsc.c > index bfc41972a0bb..d7cfb2446c13 100644 > --- a/drivers/gpu/drm/i915/display/intel_vdsc.c > +++ b/drivers/gpu/drm/i915/display/intel_vdsc.c > @@ -77,8 +77,8 @@ intel_vdsc_set_min_max_qp(struct drm_dsc_config > *vdsc_cfg, int buf, static void calculate_rc_params(struct drm_dsc_config > *vdsc_cfg) { > + int bpp = to_bpp_int(vdsc_cfg->bits_per_pixel); > int bpc = vdsc_cfg->bits_per_component; > - int bpp = vdsc_cfg->bits_per_pixel >> 4; > int qp_bpc_modifier = (bpc - 8) * 2; > int uncompressed_bpg_rate; > int first_line_bpg_offset; > @@ -148,7 +148,13 @@ calculate_rc_params(struct drm_dsc_config *vdsc_cfg) > static const s8 ofs_und8[] = { > 10, 8, 6, 4, 2, 0, -2, -4, -6, -8, -10, -10, -12, -12, > -12 > }; > - > + /* > + * For 420 format since bits_per_pixel (bpp) is set to target > bpp > * 2, > + * QP table values for target bpp 4.0 to 4.4375 (rounded to 4.0) > are > + * actually for bpp 8 to 8.875 (rounded to 4.0 * 2 i.e 8). > + * Similarly values for target bpp 4.5 to 4.8375 (rounded to > 4.5) > + * are for bpp 9 to 9.875 (rounded to 4.5 * 2 i.e 9), and so on. > + */ > bpp_i = bpp - 8; > for (buf_i = 0; buf_i < DSC_NUM_BUF_RANGES; buf_i++) { > u8 range_bpg_offset; > @@ -178,6 +184,9 @@ calculate_rc_params(struct drm_dsc_config *vdsc_cfg) > range_bpg_offset & > DSC_RANGE_BPG_OFFSET_MASK; > } > } else { > + /* fractional bpp part * 10000 (for precision up to 4 decimal > places) */ > + int fractional_bits = to_bpp_frac_dec(vdsc_cfg- > >bits_per_pixel); > + > static const s8 ofs_und6[] = { > 0, -2, -2, -4, -6, -6, -8, -8, -8, -10, -10, -12, -12, > -12, -12 > }; > @@ -191,7 +200,14 @@ calculate_rc_params(struct drm_dsc_config *vdsc_cfg) > 10, 8, 6, 4, 2, 0, -2, -4, -6, -8, -10, -10, -12, -12, > -12 > }; > > - bpp_i = (2 * (bpp - 6)); > + /* > + * QP table rows have values in increment of 0.5. > + * So 6.0 bpp to 6.4375 will have index 0, 6.5 to 6.9375 will > have index 1, > + * and so on. > + * 0.5 fractional part with 4 decimal precision becomes 5000 > + */ > + bpp_i = ((bpp - 6) + (fractional_bits < 5000 ? 0 : 1)); > + > for (buf_i = 0; buf_i < DSC_NUM_BUF_RANGES; buf_i++) { > u8 range_bpg_offset; > > @@ -279,8 +295,7 @@ int intel_dsc_compute_params(struct intel_crtc_state > *pipe_config) > /* Gen 11 does not support VBR */ > vdsc_cfg->vbr_enable = false; > > - /* Gen 11 only supports integral values of bpp */ > - vdsc_cfg->bits_per_pixel = compressed_bpp << 4; > + vdsc_cfg->bits_per_pixel = pipe_config->dsc.compressed_bpp_x16; > > /* > * According to DSC 1.2 specs in Section 4.1 if native_420 is set > -- > 2.25.1
