ALSA: hda: codecs: hdmi: disable keep-alive before audio format change

When a keep-alive (KAE) silent stream is active on an Intel HDMI/DP
codec, opening a real PCM stream reprograms the converter format and the
audio infoframe in snd_hda_hdmi_generic_pcm_prepare(). Part of that
reprogramming - the converter channel count and the channel mapping in
snd_hda_hdmi_setup_audio_infoframe() - is not safe to do while a
keep-alive stream is active. This is most visible when switching to a
multichannel PCM configuration, where the active channel count actually
changes. In that case the newly opened PCM stream plays no sound.

Add an optional hdmi_ops .prepare hook, called at the start of the
PCM prepare sequence (before the format and infoframe are touched), and
implement it for HSW+ to release keep-alive. Keep-alive is then
re-enabled as before once the new stream has been set up, in the
setup_stream op.

Fixes: 15175a4f2bbb ("ALSA: hda/hdmi: add keep-alive support for ADL-P and DG2")
Reported-by: Alexander Kaplan <alexander.kaplan@sms-medipool.de>
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/work_items/8412
Tested-by: Alexander Kaplan <alexander.kaplan@sms-medipool.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://patch.msgid.link/20260715180610.1371243-1-kai.vehmanen@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/hda/codecs/hdmi/hdmi.c b/sound/hda/codecs/hdmi/hdmi.c
index 1f4d646724edcae12de6d9f88a9557decd87ba35..a4a2f2f0540c9b7628207b7d6846281df287c67a 100644 (file)
--- a/sound/hda/codecs/hdmi/hdmi.c
+++ b/sound/hda/codecs/hdmi/hdmi.c
@@ -1688,6 +1688,9 @@ int snd_hda_hdmi_generic_pcm_prepare(struct hda_pcm_stream *hinfo,
                per_pin->channels = substream->runtime->channels;
                per_pin->setup = true;
 
+               if (spec->ops.prepare)
+                       spec->ops.prepare(codec, per_pin);
+
                if (get_wcaps(codec, cvt_nid) & AC_WCAP_STRIPE) {
                        stripe = snd_hdac_get_stream_stripe_ctl(&codec->bus->core,
                                                                substream);

diff --git a/sound/hda/codecs/hdmi/hdmi_local.h b/sound/hda/codecs/hdmi/hdmi_local.h
index 548241ad3fa99314c8e3dbf56a309451ae0fefc2..dce9a335cff28558792d0423cd613908d84b281a 100644 (file)
--- a/sound/hda/codecs/hdmi/hdmi_local.h
+++ b/sound/hda/codecs/hdmi/hdmi_local.h
@@ -74,6 +74,15 @@ struct hdmi_ops {
                            hda_nid_t pin_nid, int dev_id, u32 stream_tag,
                            int format);
 
+       /*
+        * Optional hook invoked at the beginning of the PCM prepare
+        * sequence, before the audio infoframe and stream format are
+        * (re)programmed. Used to disable keep-alive / silent stream so
+        * that the format change is not done while keep-alive is active.
+        */
+       void (*prepare)(struct hda_codec *codec,
+                       struct hdmi_spec_per_pin *per_pin);
+
        void (*pin_cvt_fixup)(struct hda_codec *codec,
                              struct hdmi_spec_per_pin *per_pin,
                              hda_nid_t cvt_nid);

diff --git a/sound/hda/codecs/hdmi/intelhdmi.c b/sound/hda/codecs/hdmi/intelhdmi.c
index 6a7882544ab77668e4fad066c0b98627c19aca94..73141046d502b5c5feeefd4e6d6471562526c83e 100644 (file)
--- a/sound/hda/codecs/hdmi/intelhdmi.c
+++ b/sound/hda/codecs/hdmi/intelhdmi.c
@@ -418,6 +418,28 @@ static void intel_not_share_assigned_cvt_nid(struct hda_codec *codec,
                intel_not_share_assigned_cvt(codec, pin_nid, dev_id, mux_idx);
 }
 
+/*
+ * prepare ops override for HSW+
+ *
+ * Disable keep-alive before the converter format and audio infoframe are
+ * reprogrammed by the PCM prepare sequence. Changing the audio format (e.g.
+ * the channel count when switching to multichannel PCM) while a keep-alive
+ * stream is active is not safe, so release keep-alive here, early in the
+ * sequence. It is re-enabled once the new stream has been set up, in
+ * i915_hsw_setup_stream().
+ */
+static void i915_hsw_prepare(struct hda_codec *codec,
+                            struct hdmi_spec_per_pin *per_pin)
+{
+       struct hdmi_spec *spec = codec->spec;
+
+       if (spec->silent_stream_type == SILENT_STREAM_KAE && per_pin->silent_stream) {
+               silent_stream_set_kae(codec, per_pin, false);
+               /* wait for pending transfers in codec to clear */
+               usleep_range(100, 200);
+       }
+}
+
 /* setup_stream ops override for HSW+ */
 static int i915_hsw_setup_stream(struct hda_codec *codec, hda_nid_t cvt_nid,
                                 hda_nid_t pin_nid, int dev_id, u32 stream_tag,
@@ -435,15 +457,16 @@ static int i915_hsw_setup_stream(struct hda_codec *codec, hda_nid_t cvt_nid,
 
        haswell_verify_D0(codec, cvt_nid, pin_nid);
 
-       if (spec->silent_stream_type == SILENT_STREAM_KAE && per_pin && per_pin->silent_stream) {
-               silent_stream_set_kae(codec, per_pin, false);
-               /* wait for pending transfers in codec to clear */
-               usleep_range(100, 200);
-       }
-
        res = snd_hda_hdmi_setup_stream(codec, cvt_nid, pin_nid, dev_id,
                                        stream_tag, format);
 
+       /*
+        * Keep-alive was disabled in i915_hsw_prepare(), re-enable it now.
+        * The pin lookup above resolves to the same per_pin that prepare
+        * used (pin_nid comes from that per_pin), so this stays balanced; a
+        * NULL per_pin only occurs on a lookup failure that also implies no
+        * active keep-alive stream to restore.
+        */
        if (spec->silent_stream_type == SILENT_STREAM_KAE && per_pin && per_pin->silent_stream) {
                usleep_range(100, 200);
                silent_stream_set_kae(codec, per_pin, true);
@@ -607,6 +630,7 @@ static int intel_hsw_common_init(struct hda_codec *codec, hda_nid_t vendor_nid,
        codec->depop_delay = 0;
        codec->auto_runtime_pm = 1;
 
+       spec->ops.prepare = i915_hsw_prepare;
        spec->ops.setup_stream = i915_hsw_setup_stream;
        spec->ops.pin_cvt_fixup = i915_pin_cvt_fixup;
        spec->ops.silent_stream = i915_set_silent_stream;