On 10/9/2022 11:50 AM, Marijn Suijten wrote:
As per the FIXME this code is entirely duplicate with what is already
provided inside drm_dsc_compute_rc_parameters(), and it is yet unknown
why this comment was put in place instead of resolved from the get-go.
Not only does it save on duplication, it would have also spared certain
issues.
For example, this code from downstream assumed dsc->bits_per_pixel to
contain an integer value, whereas the upstream drm_dsc_config struct has
it with 4 fractional bits. drm_dsc_compute_rc_parameters() already
accounts for this feat, and the sole remaining use of
dsc->bits_per_pixel inside dsi_populate_dsc_params() will be addressed
in a separate patch.
This is a nice cleanup! Thanks for doing this. I would actually like to
move towards the drm_dsc_compute_rc_parameters() API.
But I would like to hold back this change till Vinod clarifies because
Vinod had mentioned that with drm_dsc_compute_rc_parameters() he was
seeing a mismatch in the computation of two values.
slice_bpg_offset and the final_offset.
The difference between the upstream drm_dsc_compute_rc_parameters() and
dsi_populate_dsc_params() causing this was not clear to me from his
explanation earlier.
So this was left as a to-do item.
I would like this to be re-tested on pixel3 and check if this works for
vinod. If not, i think its the right time to debug why and not delay
this more.
Thanks
Abhinav
Fixes: b9080324d6ca ("drm/msm/dsi: add support for dsc data")
Signed-off-by: Marijn Suijten <marijn.suijten@xxxxxxxxxxxxxx>
---
drivers/gpu/drm/msm/dsi/dsi_host.c | 64 +++---------------------------
1 file changed, 6 insertions(+), 58 deletions(-)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 83cde4d62b68..68c39debc22f 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -21,6 +21,7 @@
#include <video/mipi_display.h>
+#include <drm/display/drm_dsc_helper.h>
#include <drm/drm_of.h>
#include "dsi.h"
@@ -1771,14 +1772,6 @@ static char bpg_offset[DSC_NUM_BUF_RANGES] = {
static int dsi_populate_dsc_params(struct drm_dsc_config *dsc)
{
- int mux_words_size;
- int groups_per_line, groups_total;
- int min_rate_buffer_size;
- int hrd_delay;
- int pre_num_extra_mux_bits, num_extra_mux_bits;
- int slice_bits;
- int data;
- int final_value, final_scale;
int i;
dsc->rc_model_size = 8192;
@@ -1804,11 +1797,11 @@ static int dsi_populate_dsc_params(struct drm_dsc_config *dsc)
if (dsc->bits_per_pixel != 8)
dsc->initial_offset = 2048; /* bpp = 12 */
- mux_words_size = 48; /* bpc == 8/10 */
- if (dsc->bits_per_component == 12)
- mux_words_size = 64;
+ if (dsc->bits_per_component <= 10)
+ dsc->mux_word_size = DSC_MUX_WORD_SIZE_8_10_BPC;
+ else
+ dsc->mux_word_size = DSC_MUX_WORD_SIZE_12_BPC;
- dsc->mux_word_size = mux_words_size;
dsc->initial_xmit_delay = 512;
dsc->initial_scale_value = 32;
dsc->first_line_bpg_offset = 12;
@@ -1820,52 +1813,7 @@ static int dsi_populate_dsc_params(struct drm_dsc_config *dsc)
dsc->rc_quant_incr_limit0 = 11;
dsc->rc_quant_incr_limit1 = 11;
- /* FIXME: need to call drm_dsc_compute_rc_parameters() so that rest of
- * params are calculated
- */
- groups_per_line = DIV_ROUND_UP(dsc->slice_width, 3);
- dsc->slice_chunk_size = DIV_ROUND_UP(dsc->slice_width * dsc->bits_per_pixel, 8);
-
- /* rbs-min */
- min_rate_buffer_size = dsc->rc_model_size - dsc->initial_offset +
- dsc->initial_xmit_delay * dsc->bits_per_pixel +
- groups_per_line * dsc->first_line_bpg_offset;
-
- hrd_delay = DIV_ROUND_UP(min_rate_buffer_size, dsc->bits_per_pixel);
-
- dsc->initial_dec_delay = hrd_delay - dsc->initial_xmit_delay;
-
- dsc->initial_scale_value = 8 * dsc->rc_model_size /
- (dsc->rc_model_size - dsc->initial_offset);
-
- slice_bits = 8 * dsc->slice_chunk_size * dsc->slice_height;
-
- groups_total = groups_per_line * dsc->slice_height;
-
- data = dsc->first_line_bpg_offset * 2048;
-
- dsc->nfl_bpg_offset = DIV_ROUND_UP(data, (dsc->slice_height - 1));
-
- pre_num_extra_mux_bits = 3 * (mux_words_size + (4 * dsc->bits_per_component + 4) - 2);
-
- num_extra_mux_bits = pre_num_extra_mux_bits - (mux_words_size -
- ((slice_bits - pre_num_extra_mux_bits) % mux_words_size));
-
- data = 2048 * (dsc->rc_model_size - dsc->initial_offset + num_extra_mux_bits);
- dsc->slice_bpg_offset = DIV_ROUND_UP(data, groups_total);
-
- data = dsc->initial_xmit_delay * dsc->bits_per_pixel;
- final_value = dsc->rc_model_size - data + num_extra_mux_bits;
- dsc->final_offset = final_value;
-
- final_scale = 8 * dsc->rc_model_size / (dsc->rc_model_size - final_value);
-
- data = (final_scale - 9) * (dsc->nfl_bpg_offset + dsc->slice_bpg_offset);
- dsc->scale_increment_interval = (2048 * dsc->final_offset) / data;
-
- dsc->scale_decrement_interval = groups_per_line / (dsc->initial_scale_value - 8);
-
- return 0;
+ return drm_dsc_compute_rc_parameters(dsc);
}
static int dsi_host_parse_dt(struct msm_dsi_host *msm_host)
