All of the link bandwidth and Data M/N calculations were assumed a bpp as
RGB format. But When we are using YCbCr 4:2:0 output format on DP,
we should change bpp calculations as YCbCr 4:2:0 format.
The pipe_bpp value was assumed RGB format, therefore, it was multiplied
with 3. But YCbCr 4:2:0 requires a multiplier value to 1.5.
Therefore we need to divide pipe_bpp to 2 while DP output uses YCbCr4:2:0
format.
- RGB format bpp = bpc x 3
- YCbCr 4:2:0 format bpp = bpc x 1.5
And it adds missed bpc values for a programming of VSC Header.
It only affects dp and edp port which use YCbCr 4:2:0 output format.
And for now, it does not consider a use case of DSC + YCbCr 4:2:0.
v2:
Addressed review comments from Ville.
Remove a changing of pipe_bpp on intel_ddi_set_pipe_settings().
Because the pipe is running at the full bpp, keep pipe_bpp as RGB
even though YCbCr 4:2:0 output format is used.
Add a link bandwidth computation for YCbCr4:2:0 output format.
Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_dp.c | 64 +++++++++++++++++++++++++++++----
1 file changed, 57 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 74f051428fb2..c6826cda8c5f 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1723,7 +1723,8 @@ void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,
struct link_config_limits {
int min_clock, max_clock;
int min_lane_count, max_lane_count;
- int min_bpp, max_bpp;
+ int min_bpp, max_bpp, bpp_step;
+ bool is_ycbcr420;
};
static bool intel_dp_source_supports_fec(struct intel_dp *intel_dp,
@@ -1833,7 +1834,7 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
int bpp, clock, lane_count;
int mode_rate, link_clock, link_avail;
- for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3) {
+ for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= limits->bpp_step) {
mode_rate = intel_dp_link_required(adjusted_mode->crtc_clock,
bpp);
@@ -1847,7 +1848,10 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
if (mode_rate <= link_avail) {
pipe_config->lane_count = lane_count;
- pipe_config->pipe_bpp = bpp;
+ if (limits->is_ycbcr420)
+ pipe_config->pipe_bpp = bpp * 2;
+ else
+ pipe_config->pipe_bpp = bpp;
pipe_config->port_clock = link_clock;
return 0;
@@ -1869,7 +1873,7 @@ intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
int bpp, clock, lane_count;
int mode_rate, link_clock, link_avail;
- for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3) {
+ for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= limits->bpp_step) {
mode_rate = intel_dp_link_required(adjusted_mode->crtc_clock,
bpp);
@@ -1883,7 +1887,10 @@ intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
if (mode_rate <= link_avail) {
pipe_config->lane_count = lane_count;
- pipe_config->pipe_bpp = bpp;
+ if (limits->is_ycbcr420)
+ pipe_config->pipe_bpp = bpp * 2;
+ else
+ pipe_config->pipe_bpp = bpp;
pipe_config->port_clock = link_clock;
return 0;
@@ -2015,6 +2022,8 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
struct link_config_limits limits;
int common_len;
int ret;
+ bool is_ycbcr420 =
+ pipe_config->output_format == INTEL_OUTPUT_FORMAT_YCBCR420 ? true : false;
common_len = intel_dp_common_len_rate_limit(intel_dp,
intel_dp->max_link_rate);
@@ -2030,6 +2039,20 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
limits.min_bpp = 6 * 3;
limits.max_bpp = intel_dp_compute_bpp(intel_dp, pipe_config);
+ limits.bpp_step = 2 * 3;
+
+ limits.is_ycbcr420 = is_ycbcr420;
+
+ if (is_ycbcr420) {
+ /*
+ * bpp value was assumed to RGB therefore it was multiplied
+ * with 3. But YCbCr 4:2:0 requires multiplier value to 1.5
+ * therefore it divides pipe_bpp to 2.
+ */
+ limits.min_bpp /= 2;
+ limits.max_bpp /= 2;
+ limits.bpp_step /= 2;
+ }
if (intel_dp_is_edp(intel_dp) && intel_dp->edp_dpcd[0] < DP_EDP_14) {
/*
@@ -2224,13 +2247,23 @@ intel_dp_compute_config(struct intel_encoder *encoder,
intel_conn_state->broadcast_rgb == INTEL_BROADCAST_RGB_LIMITED;
}
- if (!pipe_config->dsc_params.compression_enable)
- intel_link_compute_m_n(pipe_config->pipe_bpp,
+ if (!pipe_config->dsc_params.compression_enable) {
+ /*
+ * Basically, pipe_bpp value is assumed to RGB.
+ * And on the calculation of Data M and Data N, YCbCr 4:2:0
+ * output format of the number of bytes per pixel will be half
+ * the number of bytes of RGB pixel.
+ */
+ int pipe_bpp = pipe_config->output_format == INTEL_OUTPUT_FORMAT_YCBCR420 ?
+ pipe_config->pipe_bpp / 2 : pipe_config->pipe_bpp;
+
+ intel_link_compute_m_n(pipe_bpp,
pipe_config->lane_count,
adjusted_mode->crtc_clock,
pipe_config->port_clock,
&pipe_config->dp_m_n,
constant_n);
+ }
else
intel_link_compute_m_n(pipe_config->dsc_params.compressed_bpp,
pipe_config->lane_count,
@@ -4458,6 +4491,23 @@ intel_pixel_encoding_setup_vsc(struct intel_dp *intel_dp,
* 100b = 16bpc.
*/
vsc_sdp.DB17 = 0x1;
+ switch (crtc_state->pipe_bpp / 3) {
+ case 8: /* 8bpc */
+ vsc_sdp.DB17 = 0x1;
+ break;
+ case 10: /* 10bpc */
+ vsc_sdp.DB17 = 0x2;
+ break;
+ case 12: /* 12bpc */
+ vsc_sdp.DB17 = 0x3;
+ break;
+ case 16: /* 16bpc */
+ vsc_sdp.DB17 = 0x4;
+ break;
+ default:
+ DRM_DEBUG_KMS("Invalid bpp value '%d'\n", crtc_state->pipe_bpp);
+ break;
+ }
/*
* Content Type (Bits 2:0)
--
2.21.0
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