[alsa-devel] [PATCH] ALSA: hda - power setting error check

[Wang Xingchao]

codec may reject power state transition requests(reporting PS-ERROR set),
in that case we re-issue a power state setting and check error bit again.

Signed-off-by: Wang Xingchao <xingchao.wang at intel.com>
---
 sound/pci/hda/hda_codec.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index d0ca370..bb64eba 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -3526,6 +3526,7 @@ static bool snd_hda_codec_get_supported_ps(struct hda_codec *codec, hda_nid_t fg
 static void hda_set_power_state(struct hda_codec *codec, hda_nid_t fg,
 				unsigned int power_state)
 {
+	int state, count = 0;
 	if (codec->patch_ops.set_power_state) {
 		codec->patch_ops.set_power_state(codec, fg, power_state);
 		return;
@@ -3537,9 +3538,19 @@ static void hda_set_power_state(struct hda_codec *codec, hda_nid_t fg,
 		bool epss = snd_hda_codec_get_supported_ps(codec, fg, AC_PWRST_EPSS);
 		msleep(epss? 10:100);
 	}
+again:
 	snd_hda_codec_read(codec, fg, 0, AC_VERB_SET_POWER_STATE,
 			    power_state);
 	snd_hda_codec_set_power_to_all(codec, fg, power_state, true);
+	state = snd_hda_codec_read(codec, fg, 0,
+				   AC_VERB_GET_POWER_STATE, 0);
+	if (state & AC_PWRST_ERROR) {
+		/* repeat power states setting at most 10 times*/
+		if (count++ > 10)
+			snd_printk(KERN_WARNING "Power states transition reject!\n");
+		else
+			goto again;
+	}
 }
 
 /* modem wake on ring: transition from D2 to D0 in less than 2ms. For modems,
-- 
1.7.9.5