[Intel-gfx] [PATCH v6 17/28] drm/i915/dsc: Compute Rate Control parameters for DSC
Manasi Navare
manasi.d.navare at intel.com
Wed Oct 24 22:28:29 UTC 2018
From: Gaurav K Singh <gaurav.k.singh at intel.com>
This computation of RC params happens in the atomic commit phase
during compute_config() to validate if display stream compression
can be enabled for the requested mode.
v6 (From Manasi):
* Use 9 instead of 0x9 for consistency (Anusha)
v5 (From Manasi):
* Fix dim checkpatch warnings/checks
v4(From Gaurav):
* No change.Rebase on drm-tip
v3 (From Gaurav):
* Rebase on top of Manasi's latest series
* Return -ve value in case of failure scenarios (Manasi)
Fix review comments from Ville:
* Remove unnecessary comments
* Remove unnecessary paranthesis
* Add comments for few RC params calculations
v2 (From Manasi):
* Rebase Gaurav's patch from intel-gfx to gfx-internal
* Use struct drm_dsc_cfg instead of struct intel_dp
as a parameter
Cc: Manasi Navare <manasi.d.navare at intel.com>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
Signed-off-by: Gaurav K Singh <gaurav.k.singh at intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa at intel.com>
---
drivers/gpu/drm/i915/intel_vdsc.c | 127 ++++++++++++++++++++++++++++++
1 file changed, 127 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_vdsc.c b/drivers/gpu/drm/i915/intel_vdsc.c
index 351ea7d71c21..e6168a1899e1 100644
--- a/drivers/gpu/drm/i915/intel_vdsc.c
+++ b/drivers/gpu/drm/i915/intel_vdsc.c
@@ -317,6 +317,130 @@ static int get_column_index_for_rc_params(u8 bits_per_component)
}
}
+static int intel_compute_rc_parameters(struct drm_dsc_config *vdsc_cfg)
+{
+ unsigned long groups_per_line = 0;
+ unsigned long groups_total = 0;
+ unsigned long num_extra_mux_bits = 0;
+ unsigned long slice_bits = 0;
+ unsigned long hrd_delay = 0;
+ unsigned long final_scale = 0;
+ unsigned long rbs_min = 0;
+
+ /* Number of groups used to code each line of a slice */
+ groups_per_line = DIV_ROUND_UP(vdsc_cfg->slice_width,
+ DSC_RC_PIXELS_PER_GROUP);
+
+ /* chunksize in Bytes */
+ vdsc_cfg->slice_chunk_size = DIV_ROUND_UP(vdsc_cfg->slice_width *
+ vdsc_cfg->bits_per_pixel,
+ (8 * 16));
+
+ if (vdsc_cfg->convert_rgb)
+ num_extra_mux_bits = 3 * (vdsc_cfg->mux_word_size +
+ (4 * vdsc_cfg->bits_per_component + 4)
+ - 2);
+ else
+ num_extra_mux_bits = 3 * vdsc_cfg->mux_word_size +
+ (4 * vdsc_cfg->bits_per_component + 4) +
+ 2 * (4 * vdsc_cfg->bits_per_component) - 2;
+ /* Number of bits in one Slice */
+ slice_bits = 8 * vdsc_cfg->slice_chunk_size * vdsc_cfg->slice_height;
+
+ while ((num_extra_mux_bits > 0) &&
+ ((slice_bits - num_extra_mux_bits) % vdsc_cfg->mux_word_size))
+ num_extra_mux_bits--;
+
+ if (groups_per_line < vdsc_cfg->initial_scale_value - 8)
+ vdsc_cfg->initial_scale_value = groups_per_line + 8;
+
+ /* scale_decrement_interval calculation according to DSC spec 1.11 */
+ if (vdsc_cfg->initial_scale_value > 8)
+ vdsc_cfg->scale_decrement_interval = groups_per_line /
+ (vdsc_cfg->initial_scale_value - 8);
+ else
+ vdsc_cfg->scale_decrement_interval = DSC_SCALE_DECREMENT_INTERVAL_MAX;
+
+ vdsc_cfg->final_offset = vdsc_cfg->rc_model_size -
+ (vdsc_cfg->initial_xmit_delay *
+ vdsc_cfg->bits_per_pixel + 8) / 16 + num_extra_mux_bits;
+
+ if (vdsc_cfg->final_offset >= vdsc_cfg->rc_model_size) {
+ DRM_ERROR("FinalOfs < RcModelSze for this InitialXmitDelay\n");
+ return -EINVAL;
+ }
+
+ final_scale = (vdsc_cfg->rc_model_size * 8) /
+ (vdsc_cfg->rc_model_size - vdsc_cfg->final_offset);
+ if (vdsc_cfg->slice_height > 1)
+ /*
+ * NflBpgOffset is 16 bit value with 11 fractional bits
+ * hence we multiply by 2^11 for preserving the
+ * fractional part
+ */
+ vdsc_cfg->nfl_bpg_offset = DIV_ROUND_UP((vdsc_cfg->first_line_bpg_offset << 11),
+ (vdsc_cfg->slice_height - 1));
+ else
+ vdsc_cfg->nfl_bpg_offset = 0;
+
+ /* 2^16 - 1 */
+ if (vdsc_cfg->nfl_bpg_offset > 65535) {
+ DRM_ERROR("NflBpgOffset is too large for this slice height\n");
+ return -EINVAL;
+ }
+
+ /* Number of groups used to code the entire slice */
+ groups_total = groups_per_line * vdsc_cfg->slice_height;
+
+ /* slice_bpg_offset is 16 bit value with 11 fractional bits */
+ vdsc_cfg->slice_bpg_offset = DIV_ROUND_UP(((vdsc_cfg->rc_model_size -
+ vdsc_cfg->initial_offset +
+ num_extra_mux_bits) << 11),
+ groups_total);
+
+ if (final_scale > 9) {
+ /*
+ * ScaleIncrementInterval =
+ * finaloffset/((NflBpgOffset + SliceBpgOffset)*8(finalscale - 1.125))
+ * as (NflBpgOffset + SliceBpgOffset) has 11 bit fractional value,
+ * we need divide by 2^11 from pstDscCfg values
+ */
+ vdsc_cfg->scale_increment_interval =
+ (vdsc_cfg->final_offset * (1 << 11)) /
+ ((vdsc_cfg->nfl_bpg_offset +
+ vdsc_cfg->slice_bpg_offset)*
+ (final_scale - 9));
+ } else {
+ /*
+ * If finalScaleValue is less than or equal to 9, a value of 0 should
+ * be used to disable the scale increment at the end of the slice
+ */
+ vdsc_cfg->scale_increment_interval = 0;
+ }
+
+ if (vdsc_cfg->scale_increment_interval > 65535) {
+ DRM_ERROR("ScaleIncrementInterval is large for slice height\n");
+ return -EINVAL;
+ }
+
+ /*
+ * DSC spec mentions that bits_per_pixel specifies the target
+ * bits/pixel (bpp) rate that is used by the encoder,
+ * in steps of 1/16 of a bit per pixel
+ */
+ rbs_min = vdsc_cfg->rc_model_size - vdsc_cfg->initial_offset +
+ DIV_ROUND_UP(vdsc_cfg->initial_xmit_delay *
+ vdsc_cfg->bits_per_pixel, 16) +
+ groups_per_line * vdsc_cfg->first_line_bpg_offset;
+
+ hrd_delay = DIV_ROUND_UP((rbs_min * 16), vdsc_cfg->bits_per_pixel);
+ vdsc_cfg->rc_bits = (hrd_delay * vdsc_cfg->bits_per_pixel) / 16;
+ vdsc_cfg->initial_dec_delay = hrd_delay - vdsc_cfg->initial_xmit_delay;
+
+ return 0;
+}
+
+
int intel_dp_compute_dsc_params(struct intel_dp *intel_dp,
struct intel_crtc_state *pipe_config)
{
@@ -451,5 +575,8 @@ int intel_dp_compute_dsc_params(struct intel_dp *intel_dp,
vdsc_cfg->initial_scale_value = (vdsc_cfg->rc_model_size << 3) /
(vdsc_cfg->rc_model_size - vdsc_cfg->initial_offset);
+ if (intel_compute_rc_parameters(vdsc_cfg) < 0)
+ return -1;
+
return 0;
}
--
2.18.0
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