From: Clemens Ladisch <clemens@ladisch.de>
Date: Tue, 25 May 2010 07:03:40 +0000 (+0200)
Subject: ALSA: hda_intel: fix handling of non-completion stream interrupts
X-Git-Tag: v2.6.35-rc1~17^2~3^2
X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=commitdiff_plain;h=9ef04066b3e7c51ed7edc6010ac039f18f9f3617;hp=66668b6fb6861fad7f6bfef6646ac84693474c9a

ALSA: hda_intel: fix handling of non-completion stream interrupts

Check that the interrupt raised for a stream is actually a buffer
completion interrupt before handling it as one.  Otherwise, memory
errors or FIFO xruns would be interpreted as a pointer update and could
break the stream timing.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 14d895b..77e22c2 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -1097,6 +1097,7 @@ static irqreturn_t azx_interrupt(int irq, void *dev_id)
 	struct azx *chip = dev_id;
 	struct azx_dev *azx_dev;
 	u32 status;
+	u8 sd_status;
 	int i, ok;
 
 	spin_lock(&chip->reg_lock);
@@ -1110,8 +1111,10 @@ static irqreturn_t azx_interrupt(int irq, void *dev_id)
 	for (i = 0; i < chip->num_streams; i++) {
 		azx_dev = &chip->azx_dev[i];
 		if (status & azx_dev->sd_int_sta_mask) {
+			sd_status = azx_sd_readb(azx_dev, SD_STS);
 			azx_sd_writeb(azx_dev, SD_STS, SD_INT_MASK);
-			if (!azx_dev->substream || !azx_dev->running)
+			if (!azx_dev->substream || !azx_dev->running ||
+			    !(sd_status & SD_INT_COMPLETE))
 				continue;
 			/* check whether this IRQ is really acceptable */
 			ok = azx_position_ok(chip, azx_dev);