drm/amd/display: add a check for display depth validity
[why]
HDMI 2.0 fails to validate 4K@60 timing with 10 bpc
[how]
Adding a helper function that would verify if the display depth
assigned would pass a bandwidth validation.
Drop the display depth by one level till calculated pixel clk
is lower than maximum TMDS clk.
Bugzilla: https://bugs.freedesktop.org/106959
Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Tested-by: Mike Lothian <mike@fireburn.co.uk>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 1386c85..ca017c1 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -2176,6 +2176,46 @@ get_output_color_space(const struct dc_crtc_timing *dc_crtc_timing)
return color_space;
}
+static void reduce_mode_colour_depth(struct dc_crtc_timing *timing_out)
+{
+ if (timing_out->display_color_depth <= COLOR_DEPTH_888)
+ return;
+
+ timing_out->display_color_depth--;
+}
+
+static void adjust_colour_depth_from_display_info(struct dc_crtc_timing *timing_out,
+ const struct drm_display_info *info)
+{
+ int normalized_clk;
+ if (timing_out->display_color_depth <= COLOR_DEPTH_888)
+ return;
+ do {
+ normalized_clk = timing_out->pix_clk_khz;
+ /* YCbCr 4:2:0 requires additional adjustment of 1/2 */
+ if (timing_out->pixel_encoding == PIXEL_ENCODING_YCBCR420)
+ normalized_clk /= 2;
+ /* Adjusting pix clock following on HDMI spec based on colour depth */
+ switch (timing_out->display_color_depth) {
+ case COLOR_DEPTH_101010:
+ normalized_clk = (normalized_clk * 30) / 24;
+ break;
+ case COLOR_DEPTH_121212:
+ normalized_clk = (normalized_clk * 36) / 24;
+ break;
+ case COLOR_DEPTH_161616:
+ normalized_clk = (normalized_clk * 48) / 24;
+ break;
+ default:
+ return;
+ }
+ if (normalized_clk <= info->max_tmds_clock)
+ return;
+ reduce_mode_colour_depth(timing_out);
+
+ } while (timing_out->display_color_depth > COLOR_DEPTH_888);
+
+}
/*****************************************************************************/
static void
@@ -2232,6 +2272,8 @@ fill_stream_properties_from_drm_display_mode(struct dc_stream_state *stream,
stream->out_transfer_func->type = TF_TYPE_PREDEFINED;
stream->out_transfer_func->tf = TRANSFER_FUNCTION_SRGB;
+ if (stream->sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A)
+ adjust_colour_depth_from_display_info(timing_out, info);
}
static void fill_audio_info(struct audio_info *audio_info,
