Patch "ALSA: hda - Keep powering up ADCs on Cirrus codecs" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

ALSA: hda - Keep powering up ADCs on Cirrus codecs

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
alsa-hda-keep-powering-up-adcs-on-cirrus-codecs.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Takashi Iwai <[email protected]>
Date: Tue, 19 Apr 2016 22:07:50 +0200
Subject: ALSA: hda - Keep powering up ADCs on Cirrus codecs

From: Takashi Iwai <[email protected]>

commit de3df8a986b635082a1d94bae2c361d043c57106 upstream.

Although one weird behavior about the input path (inconsistent D0/D3 switch) on Cirrus CS420x codecs was fixed in the previous commit, there is still an issue on some Mac machines: the capture stream stalls when switching the ADCs on the fly. More badly, this keeps stuck until the next reboot.

The dynamic ADC switching is already a bit fragile and assuming optimistically that the chip accepts the frequent power changes. On Cirrus codecs, this doesn't seem applicable.

As a quick workaround, we pin down the ADCs to keep up in D0 when spec->dyn_adc_switch is set. In this way, the ADCs are kept up only for the system that were confirmed to be broken.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=116171

---
 sound/pci/hda/patch_cirrus.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

@@ -361,6 +361,7 @@ static int cs_parse_auto_config(struct h
 {
 	struct cs_spec *spec = codec->spec;
 	int err;
+	int i;
 
 	err = snd_hda_parse_pin_defcfg(codec, &spec->gen.autocfg, NULL, 0);
 	if (err < 0)

@@ -370,6 +371,19 @@ static int cs_parse_auto_config(struct h
 	if (err < 0)
 		return err;
 
+	/* keep the ADCs powered up when it's dynamically switchable */
+	if (spec->gen.dyn_adc_switch) {
+		unsigned int done = 0;
+		for (i = 0; i < spec->gen.input_mux.num_items; i++) {
+			int idx = spec->gen.dyn_adc_idx[i];
+			if (done & (1 << idx))
+				continue;
+			snd_hda_gen_fix_pin_power(codec,
+						  spec->gen.adc_nids[idx]);
+			done |= 1 << idx;
+		}
+	}
+
 	return 0;
 }
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/alsa-pcxhr-fix-missing-mutex-unlock.patch queue-4.4/alsa-hda-add-dock-support-for-thinkpad-x260.patch queue-4.4/alsa-hda-keep-powering-up-adcs-on-cirrus-codecs.patch queue-4.4/alsa-hda-add-pci-id-for-intel-broxton-t.patch queue-4.4/alsa-hda-don-t-trust-the-reported-actual-power-state.patch queue-4.4/alsa-hda-realtek-add-alc3234-headset-mode-for-optiplex-9020m.patch