2 nit-picks that I missed in previous versions of this patch, sorry:
diff --git a/sound/pci/hda/Kconfig b/sound/pci/hda/Kconfig
index 7ba542e45a3d..8804808410b3 100644
--- a/sound/pci/hda/Kconfig
+++ b/sound/pci/hda/Kconfig
@@ -232,4 +232,20 @@ config SND_HDA_POWER_SAVE_DEFAULT
endif
+config SND_HDA_INTEL_HDMI_SILENT_STREAM
+ bool "Enable Silent Stream always for HDMI"
+ depends on SND_HDA
nit-pick: should this be 'depends on SND_HDA_INTEL'?
if not, this 'depends on SND_HDA' is redundant, already within an
'if SND_HDA' block
+ help
+ Intel hardware has a feature called 'silent stream', that
+ keeps external HDMI receiver's analog circuitry powered on
+ avoiding 2-3 sec silence during playback start. This mechanism
+ relies on an info packet and preventing the codec from going to
+ D3. (increasing the platform static power consumption when a
+ HDMI receiver is plugged-in). 2-3 sec silence at the playback
+ start is expected whenever there is format change. (default is
+ 2 channel format).
+ Say Y to enable Silent Stream feature.
+
+endif
+
[...]
/* update ELD and jack state via audio component */
static void sync_eld_via_acomp(struct hda_codec *codec,
struct hdmi_spec_per_pin *per_pin)
{
struct hdmi_spec *spec = codec->spec;
struct hdmi_eld *eld = &spec->temp_eld;
+ bool monitor_prev, monitor_next;
mutex_lock(&per_pin->lock);
eld->monitor_present = false;
+ monitor_prev = per_pin->sink_eld.monitor_present;
eld->eld_size = snd_hdac_acomp_get_eld(&codec->core, per_pin->pin_nid,
per_pin->dev_id, &eld->monitor_present,
eld->eld_buffer, ELD_MAX_SIZE);
eld->eld_valid = (eld->eld_size > 0);
update_eld(codec, per_pin, eld, 0);
+ monitor_next = per_pin->sink_eld.monitor_present;
mutex_unlock(&per_pin->lock);
+
+ /*
+ * Power-up will call hdmi_present_sense, so the PM calls
+ * have to be done without mutex held.
+ */
+
+ if (enable_silent_stream) {
+ if (!monitor_prev && monitor_next) {
+ snd_hda_power_up_pm(codec);
nit-pick: is there a need to test the return value? I see this in
patch_hdmi.c
ret = snd_hda_power_up_pm(codec);
if (ret < 0 && pm_runtime_suspended(hda_codec_dev(codec)))
goto out;
+ silent_stream_enable(codec, per_pin);
+ } else if (monitor_prev && !monitor_next)
+ snd_hda_power_down_pm(codec);
+ }
}
static void hdmi_present_sense(struct hdmi_spec_per_pin *per_pin, int repoll)
