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 (file)
--- 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);