ALSA: hda: Modify stream stripe mask only when needed

The recent commit in HD-audio stream management for changing the
stripe control seems causing a regression on some platforms.  The
stripe control is currently used only by HDMI codec, and applying the
stripe mask unconditionally may lead to scratchy and static noises as
seen on some MacBooks.

For addressing the regression, this patch changes the stream
management code to apply the stripe mask conditionally only when the
codec driver requested.

Fixes: 9b6f7e7a29 ("ALSA: hda: program stripe bits for controller")
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=204477
Tested-by: Michael Pobega <mpobega@neverware.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191202074947.1617-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/hdaudio.h

@@ -493,6 +493,7 @@ struct hdac_stream {
 	bool prepared:1;
 	bool no_period_wakeup:1;
 	bool locked:1;
+	bool stripe:1;			/* apply stripe control */
 
 	/* timestamp */
 	unsigned long start_wallclk;	/* start + minimum wallclk */

sound/hda/hdac_stream.c

@@ -96,12 +96,14 @@ void snd_hdac_stream_start(struct hdac_stream *azx_dev, bool fresh_start)
 			      1 << azx_dev->index,
 			      1 << azx_dev->index);
 	/* set stripe control */
-	if (azx_dev->substream)
-		stripe_ctl = snd_hdac_get_stream_stripe_ctl(bus, azx_dev->substream);
-	else
-		stripe_ctl = 0;
-	snd_hdac_stream_updateb(azx_dev, SD_CTL_3B, SD_CTL_STRIPE_MASK,
-				stripe_ctl);
+	if (azx_dev->stripe) {
+		if (azx_dev->substream)
+			stripe_ctl = snd_hdac_get_stream_stripe_ctl(bus, azx_dev->substream);
+		else
+			stripe_ctl = 0;
+		snd_hdac_stream_updateb(azx_dev, SD_CTL_3B, SD_CTL_STRIPE_MASK,
+					stripe_ctl);
+	}
 	/* set DMA start and interrupt mask */
 	snd_hdac_stream_updateb(azx_dev, SD_CTL,
 				0, SD_CTL_DMA_START | SD_INT_MASK);
@@ -118,7 +120,10 @@ void snd_hdac_stream_clear(struct hdac_stream *azx_dev)
 	snd_hdac_stream_updateb(azx_dev, SD_CTL,
 				SD_CTL_DMA_START | SD_INT_MASK, 0);
 	snd_hdac_stream_writeb(azx_dev, SD_STS, SD_INT_MASK); /* to be sure */
-	snd_hdac_stream_updateb(azx_dev, SD_CTL_3B, SD_CTL_STRIPE_MASK, 0);
+	if (azx_dev->stripe) {
+		snd_hdac_stream_updateb(azx_dev, SD_CTL_3B, SD_CTL_STRIPE_MASK, 0);
+		azx_dev->stripe = 0;
+	}
 	azx_dev->running = false;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_stream_clear);

sound/pci/hda/patch_hdmi.c

@@ -32,6 +32,7 @@
 #include <sound/hda_codec.h>
 #include "hda_local.h"
 #include "hda_jack.h"
+#include "hda_controller.h"
 
 static bool static_hdmi_pcm;
 module_param(static_hdmi_pcm, bool, 0644);
@@ -1249,6 +1250,10 @@ static int hdmi_pcm_open(struct hda_pcm_stream *hinfo,
 	per_pin->cvt_nid = per_cvt->cvt_nid;
 	hinfo->nid = per_cvt->cvt_nid;
 
+	/* flip stripe flag for the assigned stream if supported */
+	if (get_wcaps(codec, per_cvt->cvt_nid) & AC_WCAP_STRIPE)
+		azx_stream(get_azx_dev(substream))->stripe = 1;
+
 	snd_hda_set_dev_select(codec, per_pin->pin_nid, per_pin->dev_id);
 	snd_hda_codec_write_cache(codec, per_pin->pin_nid, 0,
 			    AC_VERB_SET_CONNECT_SEL,