From a894f97318366d12102c15937aa6b63c21aa82b5 Mon Sep 17 00:00:00 2001 From: Mitul Golani Date: Tue, 25 Aug 2026 13:02:04 +0530 Subject: [PATCH] drm/i915/dp: Gate UHBR SST SDP splitting on sink capability 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 Reviewed-by: Suraj Kandpal Signed-off-by: Suraj Kandpal Link: https://patch.msgid.link/20260825073204.872441-1-mitulkumar.ajitkumar.golani@intel.com (cherry picked from commit b37921c9f533ca936c5b5a484c1299680c570a7e) Signed-off-by: Jani Nikula --- .../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 b7cc361fd955..43d53a98dae7 100644 --- a/drivers/gpu/drm/i915/display/intel_display_types.h +++ b/drivers/gpu/drm/i915/display/intel_display_types.h @@ -1946,6 +1946,8 @@ 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 113d767e62e9..3152122e6aef 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 @@ -4462,16 +4472,25 @@ 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]) { @@ -4771,6 +4790,7 @@ 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); @@ -4782,8 +4802,13 @@ 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. @@ -4874,13 +4899,20 @@ 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); }