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drm/amd/display: Change DSC policy from slices per column to minimum slice height

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[why] Minimum slice height is recommended by VESA DSC Spreadsheet user guide

Signed-off-by: Nikola Cornij <nikola.cornij@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Nikola Cornij 2019-07-18 19:13:26 -04:00 committed by Alex Deucher
parent 33ca0475b8
commit 7470673340
1 changed files with 35 additions and 42 deletions
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77
drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
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@ -28,6 +28,23 @@
#include "dsc.h"
#include <drm/drm_dp_helper.h>
struct dc_dsc_policy {
bool use_min_slices_h;
int max_slices_h; // Maximum available if 0
int min_sice_height; // Must not be less than 8
int max_target_bpp;
int min_target_bpp; // Minimum target bits per pixel
};
const struct dc_dsc_policy dsc_policy = {
.use_min_slices_h = true, // DSC Policy: Use minimum number of slices that fits the pixel clock
.max_slices_h = 0, // DSC Policy: Use max available slices (in our case 4 for or 8, depending on the mode)
.min_sice_height = 108, // DSC Policy: Use slice height recommended by VESA DSC Spreadsheet user guide
.max_target_bpp = 16,
.min_target_bpp = 8,
};
/* This module's internal functions */
static bool dsc_buff_block_size_from_dpcd(int dpcd_buff_block_size, int *buff_block_size)
@ -241,14 +258,6 @@ static bool intersect_dsc_caps(
return true;
}
struct dc_dsc_policy {
bool use_min_slices_h;
int max_slices_h; // Maximum available if 0
int num_slices_v;
int max_target_bpp;
int min_target_bpp; // Minimum target bits per pixel
};
static inline uint32_t dsc_div_by_10_round_up(uint32_t value)
{
return (value + 9) / 10;
@ -270,19 +279,6 @@ static inline uint32_t calc_dsc_bpp_x16(uint32_t stream_bandwidth_kbps, uint32_t
return dsc_target_bpp_x16;
}
const struct dc_dsc_policy dsc_policy = {
.use_min_slices_h = true, // DSC Policy: Use minimum number of slices that fits the pixel clock
.max_slices_h = 0, // DSC Policy: Use max available slices (in our case 4 for or 8, depending on the mode)
/* DSC Policy: Number of vertical slices set to 2 for no particular reason.
* Seems small enough to not affect the quality too much, while still providing some error
* propagation control (which may also help debugging).
*/
.num_slices_v = 16,
.max_target_bpp = 16,
.min_target_bpp = 8,
};
/* Get DSC bandwidth range based on [min_bpp, max_bpp] target bitrate range, and timing's pixel clock
* and uncompressed bandwidth.
*/
@ -528,8 +524,8 @@ static bool setup_dsc_config(
int sink_per_slice_throughput_mps;
int branch_max_throughput_mps = 0;
bool is_dsc_possible = false;
int num_slices_v;
int pic_height;
int slice_height;
memset(dsc_cfg, 0, sizeof(struct dc_dsc_config));
@ -615,7 +611,7 @@ static bool setup_dsc_config(
if (!is_dsc_possible)
goto done;
// DSC slicing
// Slice width (i.e. number of slices per line)
max_slices_h = get_max_dsc_slices(dsc_common_caps.slice_caps);
while (max_slices_h > 0) {
@ -678,29 +674,26 @@ static bool setup_dsc_config(
dsc_cfg->num_slices_h = num_slices_h;
slice_width = pic_width / num_slices_h;
// Vertical number of slices: start from policy and pick the first one that height is divisible by.
// For 4:2:0 make sure the slice height is divisible by 2 as well.
num_slices_v = dsc_policy.num_slices_v;
if (num_slices_v < 1)
num_slices_v = 1;
while (num_slices_v >= 1) {
if (timing->pixel_encoding == PIXEL_ENCODING_YCBCR420) {
int slice_height = pic_height / num_slices_v;
if (pic_height % num_slices_v == 0 && slice_height % 2 == 0)
break;
} else if (pic_height % num_slices_v == 0)
break;
num_slices_v--;
}
dsc_cfg->num_slices_v = num_slices_v;
is_dsc_possible = slice_width <= dsc_common_caps.max_slice_width;
if (!is_dsc_possible)
goto done;
// Slice height (i.e. number of slices per column): start with policy and pick the first one that height is divisible by.
// For 4:2:0 make sure the slice height is divisible by 2 as well.
slice_height = min(dsc_policy.min_sice_height, pic_height);
while (slice_height < pic_height && (pic_height % slice_height != 0 ||
(timing->pixel_encoding == PIXEL_ENCODING_YCBCR420 && slice_height % 2 != 0)))
slice_height++;
if (timing->pixel_encoding == PIXEL_ENCODING_YCBCR420) // For the case when pic_height < dsc_policy.min_sice_height
is_dsc_possible = (slice_height % 2 == 0);
if (!is_dsc_possible)
goto done;
dsc_cfg->num_slices_v = pic_height/slice_height;
// Final decission: can we do DSC or not?
if (is_dsc_possible) {
// Fill out the rest of DSC settings