From: Mario Limonciello <mario.limoncie...@amd.com>
[Why]
DP validation may fail with multiple displays and higher color depths.
The sink may support others though.
[How]
When DP bandwidth validation fails, progressively fallback through:
- YUV422 8bpc (bandwidth efficient)
- YUV422 6bpc (reduced color depth)
- YUV420 (last resort)
This resolves cases where displays would show no image due to insufficient
DP link bandwidth for the requested RGB mode.
Suggested-by: Mauri Carvalho <mcarval...@lenovo.com>
Reviewed-by: Wayne Lin <wayne....@amd.com>
Signed-off-by: Mario Limonciello <mario.limoncie...@amd.com>
Signed-off-by: Ray Wu <ray...@amd.com>
---
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 45 +++++++++++++++----
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h | 1 +
2 files changed, 37 insertions(+), 9 deletions(-)
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 1f9c56c288b2..5a62a1967a2d 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -6406,7 +6406,8 @@ static void fill_stream_properties_from_drm_display_mode(
&& aconnector->force_yuv420_output)
timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
else if ((connector->display_info.color_formats &
DRM_COLOR_FORMAT_YCBCR422)
- && stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
+ && aconnector
+ && aconnector->force_yuv422_output)
timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR422;
else if ((connector->display_info.color_formats &
DRM_COLOR_FORMAT_YCBCR444)
&& stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
@@ -7668,6 +7669,7 @@ create_validate_stream_for_sink(struct drm_connector
*connector,
bpc_limit = 8;
do {
+ drm_dbg_kms(connector->dev, "Trying with %d bpc\n",
requested_bpc);
stream = create_stream_for_sink(connector, drm_mode,
dm_state, old_stream,
requested_bpc);
@@ -7703,16 +7705,41 @@ create_validate_stream_for_sink(struct drm_connector
*connector,
} while (stream == NULL && requested_bpc >= bpc_limit);
- if ((dc_result == DC_FAIL_ENC_VALIDATE ||
- dc_result == DC_EXCEED_DONGLE_CAP) &&
- !aconnector->force_yuv420_output) {
- DRM_DEBUG_KMS("%s:%d Retry forcing yuv420 encoding\n",
- __func__, __LINE__);
-
- aconnector->force_yuv420_output = true;
+ switch (dc_result) {
+ /*
+ * If we failed to validate DP bandwidth stream with the requested RGB
color depth,
+ * we try to fallback and configure in order:
+ * YUV422 (8bpc, 6bpc)
+ * YUV420 (8bpc, 6bpc)
+ */
+ case DC_FAIL_ENC_VALIDATE:
+ case DC_EXCEED_DONGLE_CAP:
+ case DC_NO_DP_LINK_BANDWIDTH:
+ /* recursively entered twice and already tried both YUV422 and
YUV420 */
+ if (aconnector->force_yuv422_output &&
aconnector->force_yuv420_output)
+ break;
+ /* first failure; try YUV422 */
+ if (!aconnector->force_yuv422_output) {
+ drm_dbg_kms(connector->dev, "%s:%d Validation failed
with %d, retrying w/ YUV422\n",
+ __func__, __LINE__, dc_result);
+ aconnector->force_yuv422_output = true;
+ /* recursively entered and YUV422 failed, try YUV420 */
+ } else if (!aconnector->force_yuv420_output) {
+ drm_dbg_kms(connector->dev, "%s:%d Validation failed
with %d, retrying w/ YUV420\n",
+ __func__, __LINE__, dc_result);
+ aconnector->force_yuv420_output = true;
+ }
stream = create_validate_stream_for_sink(connector, drm_mode,
- dm_state, old_stream);
+ dm_state, old_stream);
+ aconnector->force_yuv422_output = false;
aconnector->force_yuv420_output = false;
+ break;
+ case DC_OK:
+ break;
+ default:
+ drm_dbg_kms(connector->dev, "%s:%d Unhandled validation failure
%d\n",
+ __func__, __LINE__, dc_result);
+ break;
}
return stream;
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index ce74125c713e..2967cd28efe4 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -794,6 +794,7 @@ struct amdgpu_dm_connector {
bool fake_enable;
bool force_yuv420_output;
+ bool force_yuv422_output;
struct dsc_preferred_settings dsc_settings;
union dp_downstream_port_present mst_downstream_port_present;
/* Cached display modes */
--
2.43.0
