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drm/i915/audio: treat UHBR SST like MST for cpu_transcoder signalling

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Both DP MST and UHBR SST require the audio component to use a real
cpu_transcoder (>= 0) value to identify the audio stream on a port.
For DP MST this was already handled; for UHBR SST it was not, causing
pin_eld_notify() to signal cpu_transcoder = -1 (the legacy SST sentinel)
and find_audio_state() to skip the per-transcoder entry for the UHBR
stream.

After suspend/resume or replug, the ELD lookup fails and audio goes
silent. Fix by detecting UHBR SST alongside DP MST when deciding
whether a real cpu_transcoder value must be used for audio state
addressing, in both the pin_eld_notify() signalling and the
find_audio_state() lookup paths.

--v2:
- Commit message and comment update. (Suraj)
- Change function name has_mst_transcoder. (Suraj)
- Avoid Live crtc access in find_audio_state. (Suraj)

--v3:
- Minor comment changes to avoid MST over 128b/132b confusion. (Suraj)

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patch.msgid.link/20260708113558.1863316-1-mitulkumar.ajitkumar.golani@intel.com
This commit is contained in:
Kai Vehmanen 2026-07-08 17:05:58 +05:30 committed by Suraj Kandpal
parent a78d11e785
commit e6d534ed11
2 changed files with 42 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

55
drivers/gpu/drm/i915/display/intel_audio.c
View File

@ -38,6 +38,7 @@
#include "intel_de.h"
#include "intel_display_types.h"
#include "intel_display_wa.h"
#include "intel_dp.h"
#include "intel_lpe_audio.h"
/**
@ -696,6 +697,13 @@ static void ibx_audio_codec_enable(struct intel_encoder *encoder,
mutex_unlock(&display->audio.mutex);
}
static
bool intel_audio_needs_cpu_transcoder_id(const struct intel_crtc_state *crtc_state)
{
return intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP_MST) ||
intel_dp_is_uhbr(crtc_state);
}
bool intel_audio_compute_config(struct intel_encoder *encoder,
struct intel_crtc_state *crtc_state,
struct drm_connector_state *conn_state)
@ -762,6 +770,8 @@ void intel_audio_codec_enable(struct intel_encoder *encoder,
audio_state = &display->audio.state[cpu_transcoder];
audio_state->encoder = encoder;
audio_state->needs_cpu_transcoder_id =
intel_audio_needs_cpu_transcoder_id(crtc_state);
BUILD_BUG_ON(sizeof(audio_state->eld) != sizeof(crtc_state->eld));
memcpy(audio_state->eld, crtc_state->eld, sizeof(audio_state->eld));
@ -769,8 +779,12 @@ void intel_audio_codec_enable(struct intel_encoder *encoder,
if (acomp && acomp->base.audio_ops &&
acomp->base.audio_ops->pin_eld_notify) {
/* audio drivers expect cpu_transcoder = -1 to indicate Non-MST cases */
if (!intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP_MST))
/*
* Audio drivers expect cpu_transcoder = -1 to indicate
* Non-MST/HBR cases. MST and UHBR SST are addressed by
* a real cpu_transcoder.
*/
if (!intel_audio_needs_cpu_transcoder_id(crtc_state))
cpu_transcoder = -1;
acomp->base.audio_ops->pin_eld_notify(acomp->base.audio_ops->audio_ptr,
(int)port, (int)cpu_transcoder);
@ -819,14 +833,19 @@ void intel_audio_codec_disable(struct intel_encoder *encoder,
audio_state = &display->audio.state[cpu_transcoder];
audio_state->encoder = NULL;
audio_state->needs_cpu_transcoder_id = false;
memset(audio_state->eld, 0, sizeof(audio_state->eld));
mutex_unlock(&display->audio.mutex);
if (acomp && acomp->base.audio_ops &&
acomp->base.audio_ops->pin_eld_notify) {
/* audio drivers expect cpu_transcoder = -1 to indicate Non-MST cases */
if (!intel_crtc_has_type(old_crtc_state, INTEL_OUTPUT_DP_MST))
/*
* Audio drivers expect cpu_transcoder = -1 to indicate
* Non-MST/HBR cases. MST and UHBR SST are addressed by
* a real cpu_transcoder.
*/
if (!intel_audio_needs_cpu_transcoder_id(old_crtc_state))
cpu_transcoder = -1;
acomp->base.audio_ops->pin_eld_notify(acomp->base.audio_ops->audio_ptr,
(int)port, (int)cpu_transcoder);
@ -1118,18 +1137,24 @@ static int intel_audio_component_get_cdclk_freq(struct device *kdev)
}
/*
* get the intel audio state according to the parameter port and cpu_transcoder
* MST & (cpu_transcoder >= 0): return the audio.state[cpu_transcoder].encoder],
* when port is matched
* MST & (cpu_transcoder < 0): this is invalid
* Non-MST & (cpu_transcoder >= 0): only cpu_transcoder = 0 (the first device entry)
* will get the right intel_encoder with port matched
* Non-MST & (cpu_transcoder < 0): get the right intel_encoder with port matched
* Get the intel audio state for a given (port, cpu_transcoder).
*
* Streams are addressed either by a real cpu_transcoder (DP MST and UHBR SST,
* i.e. entries whose stored needs_cpu_transcoder_id is true) or by port alone
* (legacy SST). Both the signalling side (pin_eld_notify()) and the lookup
* side use the same predicate, so the two are symmetric.
*
* cpu_transcoder >= 0 & needs_cpu_transcoder_id: return audio.state[cpu_transcoder]
* when the port matches.
* cpu_transcoder < 0 & !needs_cpu_transcoder_id: return the first port-matching
* entry.
* cpu_transcoder = 0 & !needs_cpu_transcoder_id: falls to the port-only
* loop so the first device entry of a legacy SST port is still found.
*/
static struct intel_audio_state *find_audio_state(struct intel_display *display,
int port, int cpu_transcoder)
{
/* MST */
/* MST, or UHBR SST. */
if (cpu_transcoder >= 0) {
struct intel_audio_state *audio_state;
struct intel_encoder *encoder;
@ -1142,11 +1167,11 @@ static struct intel_audio_state *find_audio_state(struct intel_display *display,
encoder = audio_state->encoder;
if (encoder && encoder->port == port &&
encoder->type == INTEL_OUTPUT_DP_MST)
audio_state->needs_cpu_transcoder_id)
return audio_state;
}
/* Non-MST */
/* Legacy SST. */
if (cpu_transcoder > 0)
return NULL;
@ -1158,7 +1183,7 @@ static struct intel_audio_state *find_audio_state(struct intel_display *display,
encoder = audio_state->encoder;
if (encoder && encoder->port == port &&
encoder->type != INTEL_OUTPUT_DP_MST)
!audio_state->needs_cpu_transcoder_id)
return audio_state;
}

2
drivers/gpu/drm/i915/display/intel_display_core.h
View File

@ -97,6 +97,8 @@ struct intel_wm_funcs {
struct intel_audio_state {
struct intel_encoder *encoder;
u8 eld[MAX_ELD_BYTES];
/* MST, or SST on UHBR link */
bool needs_cpu_transcoder_id;
};
struct intel_audio {