SDP splitting for 128b/132b (UHBR) SST audio must only be enabled when
the sink advertises support for it. Previously sdp_split_enable
was set for every UHBR SST stream carrying audio, regardless of sink
capability.
In MST mode SDP splitting is inherently supported, so the sink
capability check (DP_SST_SPLIT_SDP_CAP) is applied only to the SST path.
Fixes: 8853750dbad8 ("drm/i915: Enable SDP split for DP2.0")
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Mitul Golani <[email protected]>
Reviewed-by: Suraj Kandpal <[email protected]>
--v2:
- Correct the name in the intel_dp struct. (Suraj)
- Add the Fixes tag. (Suraj)
- Explain the reasoning for guarding SST separately from MST. (Suraj)
- Add a separate helper to read capabilities. (Suraj)
--v3:
- Use drm_dp_dpcd_read instead of drm_dp_dpcd_readb. (Suraj)
- Move Assisted-by above Signed-off-by. (Suraj)
- Add the versioning diff. (Suraj)
---
.../drm/i915/display/intel_display_types.h | 2 +
drivers/gpu/drm/i915/display/intel_dp.c | 44 ++++++++++++++++---
2 files changed, 40 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
b/drivers/gpu/drm/i915/display/intel_display_types.h
index 20a07ea06b5e..5f0fe18c0614 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1951,6 +1951,8 @@ struct intel_dp {
bool colorimetry_support;
+ bool sst_split_sdp_support;
+
struct {
enum transcoder transcoder;
struct mutex lock;
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
b/drivers/gpu/drm/i915/display/intel_dp.c
index 6b60e0a1c8ee..0cd5e6b5034c 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3409,12 +3409,22 @@ intel_dp_audio_compute_config(struct intel_encoder
*encoder,
struct intel_crtc_state *pipe_config,
struct drm_connector_state *conn_state)
{
+ struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
+
pipe_config->has_audio =
intel_dp_has_audio(encoder, conn_state) &&
intel_audio_compute_config(encoder, pipe_config, conn_state);
pipe_config->sdp_split_enable = pipe_config->has_audio &&
intel_dp_is_uhbr(pipe_config);
+
+ /*
+ * SDP splitting for UHBR audio requires explicit sink capability in
+ * SST mode, whereas in MST mode it is inherently supported.
+ */
+ if (pipe_config->sdp_split_enable &&
+ !intel_crtc_has_type(pipe_config, INTEL_OUTPUT_DP_MST))
+ pipe_config->sdp_split_enable = intel_dp->sst_split_sdp_support;
}
void
@@ -4456,16 +4466,25 @@ void intel_dp_configure_protocol_converter(struct
intel_dp *intel_dp,
str_enable_disable(tmp));
}
-static bool intel_dp_get_colorimetry_status(struct intel_dp *intel_dp)
+static u8 intel_dp_read_dprx_feature_enum(struct intel_dp *intel_dp)
{
u8 dprx = 0;
- if (drm_dp_dpcd_readb(&intel_dp->aux, DP_DPRX_FEATURE_ENUMERATION_LIST,
- &dprx) != 1)
- return false;
+ drm_dp_dpcd_read_data(&intel_dp->aux, DP_DPRX_FEATURE_ENUMERATION_LIST,
+ &dprx, sizeof(dprx));
+ return dprx;
+}
+
+static bool intel_dp_get_colorimetry_status(u8 dprx)
+{
return dprx & DP_VSC_SDP_EXT_FOR_COLORIMETRY_SUPPORTED;
}
+static bool intel_dp_get_sst_split_sdp_status(u8 dprx)
+{
+ return dprx & DP_SST_SPLIT_SDP_CAP;
+}
+
static int intel_dp_read_dsc_dpcd(struct drm_dp_aux *aux,
u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
{
@@ -4765,6 +4784,7 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp, struct
intel_connector *connector
{
struct intel_display *display = to_intel_display(intel_dp);
int ret;
+ u8 dprx;
/* this function is meant to be called only once */
drm_WARN_ON(display->drm, intel_dp->dpcd[DP_DPCD_REV] != 0);
@@ -4776,8 +4796,13 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp, struct
intel_connector *connector
drm_dp_is_branch(intel_dp->dpcd));
intel_init_dpcd_quirks(intel_dp, &intel_dp->desc.ident);
+ dprx = intel_dp_read_dprx_feature_enum(intel_dp);
+
intel_dp->colorimetry_support =
- intel_dp_get_colorimetry_status(intel_dp);
+ intel_dp_get_colorimetry_status(dprx);
+
+ intel_dp->sst_split_sdp_support =
+ intel_dp_get_sst_split_sdp_status(dprx);
/*
* Read the eDP display control registers.
@@ -4868,13 +4893,20 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
* the OUI/ID since we know it won't change.
*/
if (!intel_dp_is_edp(intel_dp)) {
+ u8 dprx;
+
drm_dp_read_desc(&intel_dp->aux, &intel_dp->desc,
drm_dp_is_branch(intel_dp->dpcd));
intel_init_dpcd_quirks(intel_dp, &intel_dp->desc.ident);
+ dprx = intel_dp_read_dprx_feature_enum(intel_dp);
+
intel_dp->colorimetry_support =
- intel_dp_get_colorimetry_status(intel_dp);
+ intel_dp_get_colorimetry_status(dprx);
+
+ intel_dp->sst_split_sdp_support =
+ intel_dp_get_sst_split_sdp_status(dprx);
intel_dp_update_sink_caps(intel_dp);
}
--
2.48.1
