ALSA: cs5535audio: turn off PCM properly if closing the audio device

As per <http://dev.laptop.org/ticket/1420>, we need to properly turn off
the PCM if we're closing the device in order to save power.  This also
causes the MIC led to turn off properly.

Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Signed-off-by: Andres Salomon <dilinger@debian.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/cs5535audio/cs5535audio_pcm.c b/sound/pci/cs5535audio/cs5535audio_pcm.c
index cdcda87..6aa0c19 100644
--- a/sound/pci/cs5535audio/cs5535audio_pcm.c
+++ b/sound/pci/cs5535audio/cs5535audio_pcm.c
@@ -260,6 +260,9 @@
 	err = cs5535audio_build_dma_packets(cs5535au, dma, substream,
 					    params_periods(hw_params),
 					    params_period_bytes(hw_params));
+	if (!err)
+		dma->pcm_open_flag = 1;
+
 	return err;
 }
 
@@ -268,6 +271,15 @@
 	struct cs5535audio *cs5535au = snd_pcm_substream_chip(substream);
 	struct cs5535audio_dma *dma = substream->runtime->private_data;
 
+	if (dma->pcm_open_flag) {
+		if (substream == cs5535au->playback_substream)
+			snd_ac97_update_power(cs5535au->ac97,
+					AC97_PCM_FRONT_DAC_RATE, 0);
+		else
+			snd_ac97_update_power(cs5535au->ac97,
+					AC97_PCM_LR_ADC_RATE, 0);
+		dma->pcm_open_flag = 0;
+	}
 	cs5535audio_clear_dma_packets(cs5535au, dma, substream);
 	return snd_pcm_lib_free_pages(substream);
 }