From: Nikola Cornij <nikola.cornij@xxxxxxx>
[why] Minimum slice height is recommended by VESA DSC Spreadsheet user guide
Signed-off-by: Nikola Cornij <nikola.cornij@xxxxxxx>
Reviewed-by: Jun Lei <Jun.Lei@xxxxxxx>
Acked-by: Leo Li <sunpeng.li@xxxxxxx>
---
drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c | 71 ++++++++++-----------
1 file changed, 32 insertions(+), 39 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c b/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
index ef5f84a144c3..5995bcdfed54 100644
--- a/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
+++ b/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
@@ -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.
+ 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.
- 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;
+ slice_height = min(dsc_policy.min_sice_height, pic_height);
- num_slices_v--;
- }
+ while (slice_height < pic_height && (pic_height % slice_height != 0 ||
+ (timing->pixel_encoding == PIXEL_ENCODING_YCBCR420 && slice_height % 2 != 0)))
+ slice_height++;
- dsc_cfg->num_slices_v = num_slices_v;
+ 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);
- is_dsc_possible = slice_width <= dsc_common_caps.max_slice_width;
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
--
2.22.0
_______________________________________________
amd-gfx mailing list
amd-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
