ALSA: AACI: fix multiple IRQ claiming

Claiming the IRQ each time a playback or capture interface is opened
is wasteful; the second copy of the registered handler is identical to
the first and just wastes resources.  Track the number of opens and
only register the handler when necessary.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/sound/arm/aaci.c b/sound/arm/aaci.c
index 24d3013c02312e7773ae1a864ed87e0ba1b571ee..65685afd8f77c65d16cd2551626c04b8066b08fe 100644 (file)
--- a/sound/arm/aaci.c
+++ b/sound/arm/aaci.c
@@ -370,7 +370,7 @@ static int __aaci_pcm_open(struct aaci *aaci,
                           struct aaci_runtime *aacirun)
 {
        struct snd_pcm_runtime *runtime = substream->runtime;
-       int ret;
+       int ret = 0;
 
        aacirun->substream = substream;
        runtime->private_data = aacirun;
@@ -391,14 +391,15 @@ static int __aaci_pcm_open(struct aaci *aaci,
         */
        runtime->hw.fifo_size = aaci->fifosize * 2;
 
-       ret = request_irq(aaci->dev->irq[0], aaci_irq, IRQF_SHARED|IRQF_DISABLED,
-                         DRIVER_NAME, aaci);
-       if (ret)
-               goto out;
-
-       return 0;
+       mutex_lock(&aaci->irq_lock);
+       if (!aaci->users++) {
+               ret = request_irq(aaci->dev->irq[0], aaci_irq,
+                          IRQF_SHARED | IRQF_DISABLED, DRIVER_NAME, aaci);
+               if (ret != 0)
+                       aaci->users--;
+       }
+       mutex_unlock(&aaci->irq_lock);
 
- out:
        return ret;
 }
 
@@ -414,7 +415,11 @@ static int aaci_pcm_close(struct snd_pcm_substream *substream)
        WARN_ON(aacirun->cr & CR_EN);
 
        aacirun->substream = NULL;
-       free_irq(aaci->dev->irq[0], aaci);
+
+       mutex_lock(&aaci->irq_lock);
+       if (!--aaci->users)
+               free_irq(aaci->dev->irq[0], aaci);
+       mutex_unlock(&aaci->irq_lock);
 
        return 0;
 }
@@ -943,6 +948,7 @@ static struct aaci * __devinit aaci_init_card(struct amba_device *dev)
 
        aaci = card->private_data;
        mutex_init(&aaci->ac97_sem);
+       mutex_init(&aaci->irq_lock);
        aaci->card = card;
        aaci->dev = dev;
 

diff --git a/sound/arm/aaci.h b/sound/arm/aaci.h
index 6a4a2eebdda1c46955215b434022699e4819556e..04c4568413f457c464be471e611cdb9e6ae2f910 100644 (file)
--- a/sound/arm/aaci.h
+++ b/sound/arm/aaci.h
@@ -226,6 +226,8 @@ struct aaci {
        struct snd_card         *card;
        void                    __iomem *base;
        unsigned int            fifosize;
+       unsigned int            users;
+       struct mutex            irq_lock;
 
        /* AC'97 */
        struct mutex            ac97_sem;