Commit 27998631 authored by Gaurav K Singh's avatar Gaurav K Singh Committed by Manasi Navare

drm/i915/dsc: Compute Rate Control parameters for DSC

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.

v7 (From Manasi):
* Use DRM_DEBUG instead of DRM_ERROR (Ville)
* Use Error numberinstead of -1 (Ville)
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@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarGaurav K Singh <gaurav.k.singh@intel.com>
Signed-off-by: default avatarManasi Navare <manasi.d.navare@intel.com>
Reviewed-by: default avatarAnusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181128202628.20238-5-manasi.d.navare@intel.com
parent 168243c1
...@@ -318,6 +318,129 @@ static int get_column_index_for_rc_params(u8 bits_per_component) ...@@ -318,6 +318,129 @@ 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_DEBUG_KMS("FinalOfs < RcModelSze for this InitialXmitDelay\n");
return -ERANGE;
}
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_DEBUG_KMS("NflBpgOffset is too large for this slice height\n");
return -ERANGE;
}
/* 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_DEBUG_KMS("ScaleIncrementInterval is large for slice height\n");
return -ERANGE;
}
/*
* 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, int intel_dp_compute_dsc_params(struct intel_dp *intel_dp,
struct intel_crtc_state *pipe_config) struct intel_crtc_state *pipe_config)
{ {
...@@ -452,5 +575,5 @@ int intel_dp_compute_dsc_params(struct intel_dp *intel_dp, ...@@ -452,5 +575,5 @@ int intel_dp_compute_dsc_params(struct intel_dp *intel_dp,
vdsc_cfg->initial_scale_value = (vdsc_cfg->rc_model_size << 3) / vdsc_cfg->initial_scale_value = (vdsc_cfg->rc_model_size << 3) /
(vdsc_cfg->rc_model_size - vdsc_cfg->initial_offset); (vdsc_cfg->rc_model_size - vdsc_cfg->initial_offset);
return 0; return intel_compute_rc_parameters(vdsc_cfg);
} }
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