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drm/amd/display: Reduce HDMI pixel encoding if max clock is exceeded 

For high-res (8K) or HFR (4K120) displays, using uncompressed pixel
formats like YCbCr444 would exceed the bandwidth of HDMI 2.0, so the
"interesting" modes would be disabled, leaving only low-res or low
framerate modes.

This change lowers the pixel encoding to 4:2:2 or 4:2:0 if the max TMDS
clock is exceeded. Verified that 8K30 and 4K120 are now available and
working with a Samsung Q900R over an HDMI 2.0b link from a Radeon 5700.

Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Thomas Anderson <thomasanderson@google.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
alistair/sunxi64-5.5-dsi
Thomas Anderson 2019-12-02 13:47:13 -08:00 committed by Alex Deucher
parent 7aec9ec1cf
commit 840c90fce6
1 changed files with 23 additions and 22 deletions
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45
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
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@ -3356,27 +3356,21 @@ 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)
static bool adjust_colour_depth_from_display_info(
struct dc_crtc_timing *timing_out,
const struct drm_display_info *info)
{
enum dc_color_depth depth = timing_out->display_color_depth;
int normalized_clk;
if (timing_out->display_color_depth <= COLOR_DEPTH_888)
return;
do {
normalized_clk = timing_out->pix_clk_100hz / 10;
/* 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) {
switch (depth) {
case COLOR_DEPTH_888:
break;
case COLOR_DEPTH_101010:
normalized_clk = (normalized_clk * 30) / 24;
break;
@ -3387,14 +3381,15 @@ static void adjust_colour_depth_from_display_info(struct dc_crtc_timing *timing_
normalized_clk = (normalized_clk * 48) / 24;
break;
default:
return;
/* The above depths are the only ones valid for HDMI. */
return false;
}
if (normalized_clk <= info->max_tmds_clock)
return;
reduce_mode_colour_depth(timing_out);
} while (timing_out->display_color_depth > COLOR_DEPTH_888);
if (normalized_clk <= info->max_tmds_clock) {
timing_out->display_color_depth = depth;
return true;
}
} while (--depth > COLOR_DEPTH_666);
return false;
}
static void fill_stream_properties_from_drm_display_mode(
@ -3474,8 +3469,14 @@ static void fill_stream_properties_from_drm_display_mode(
stream->out_transfer_func->type = TF_TYPE_PREDEFINED;
stream->out_transfer_func->tf = TRANSFER_FUNCTION_SRGB;
if (stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
adjust_colour_depth_from_display_info(timing_out, info);
if (stream->signal == SIGNAL_TYPE_HDMI_TYPE_A) {
if (!adjust_colour_depth_from_display_info(timing_out, info) &&
drm_mode_is_420_also(info, mode_in) &&
timing_out->pixel_encoding != PIXEL_ENCODING_YCBCR420) {
timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
adjust_colour_depth_from_display_info(timing_out, info);
}
}
}
static void fill_audio_info(struct audio_info *audio_info,