ALSA: ice1724 - Dynamic MIDI TX irq control

MIDI_TX IRQ seems always pending when any bytes on FIFO is available.
Thus, it's better to enable MPU_TX only when any bytres are really
stored in the substream, and disables immediately when the queue
becomes empty.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/ice1712/ice1724.c b/sound/pci/ice1712/ice1724.c
index bb8d8c766b9d1f5ee5e08f85a8a36694ac1b8058..eb7872dec5aec94ed167e7d99c6dbd2be0f09491 100644 (file)
--- a/sound/pci/ice1712/ice1724.c
+++ b/sound/pci/ice1712/ice1724.c
@@ -241,6 +241,8 @@ get_rawmidi_substream(struct snd_ice1712 *ice, unsigned int stream)
                                struct snd_rawmidi_substream, list);
 }
 
+static void enable_midi_irq(struct snd_ice1712 *ice, u8 flag, int enable);
+
 static void vt1724_midi_write(struct snd_ice1712 *ice)
 {
        struct snd_rawmidi_substream *s;
@@ -254,6 +256,11 @@ static void vt1724_midi_write(struct snd_ice1712 *ice)
                for (i = 0; i < count; ++i)
                        outb(buffer[i], ICEREG1724(ice, MPU_DATA));
        }
+       /* mask irq when all bytes have been transmitted.
+        * enabled again in output_trigger when the new data comes in.
+        */
+       enable_midi_irq(ice, VT1724_IRQ_MPU_TX,
+                       !snd_rawmidi_transmit_empty(s));
 }
 
 static void vt1724_midi_read(struct snd_ice1712 *ice)
@@ -272,31 +279,34 @@ static void vt1724_midi_read(struct snd_ice1712 *ice)
        }
 }
 
-static void vt1724_enable_midi_irq(struct snd_rawmidi_substream *substream,
-                                  u8 flag, int enable)
+/* call with ice->reg_lock */
+static void enable_midi_irq(struct snd_ice1712 *ice, u8 flag, int enable)
 {
-       struct snd_ice1712 *ice = substream->rmidi->private_data;
-       u8 mask;
-
-       spin_lock_irq(&ice->reg_lock);
-       mask = inb(ICEREG1724(ice, IRQMASK));
+       u8 mask = inb(ICEREG1724(ice, IRQMASK));
        if (enable)
                mask &= ~flag;
        else
                mask |= flag;
        outb(mask, ICEREG1724(ice, IRQMASK));
+}
+
+static void vt1724_enable_midi_irq(struct snd_rawmidi_substream *substream,
+                                  u8 flag, int enable)
+{
+       struct snd_ice1712 *ice = substream->rmidi->private_data;
+
+       spin_lock_irq(&ice->reg_lock);
+       enable_midi_irq(ice, flag, enable);
        spin_unlock_irq(&ice->reg_lock);
 }
 
 static int vt1724_midi_output_open(struct snd_rawmidi_substream *s)
 {
-       vt1724_enable_midi_irq(s, VT1724_IRQ_MPU_TX, 1);
        return 0;
 }
 
 static int vt1724_midi_output_close(struct snd_rawmidi_substream *s)
 {
-       vt1724_enable_midi_irq(s, VT1724_IRQ_MPU_TX, 0);
        return 0;
 }
 
@@ -311,6 +321,7 @@ static void vt1724_midi_output_trigger(struct snd_rawmidi_substream *s, int up)
                vt1724_midi_write(ice);
        } else {
                ice->midi_output = 0;
+               enable_midi_irq(ice, VT1724_IRQ_MPU_TX, 0);
        }
        spin_unlock_irqrestore(&ice->reg_lock, flags);
 }
@@ -320,6 +331,7 @@ static void vt1724_midi_output_drain(struct snd_rawmidi_substream *s)
        struct snd_ice1712 *ice = s->rmidi->private_data;
        unsigned long timeout;
 
+       vt1724_enable_midi_irq(s, VT1724_IRQ_MPU_TX, 0);
        /* 32 bytes should be transmitted in less than about 12 ms */
        timeout = jiffies + msecs_to_jiffies(15);
        do {
@@ -389,24 +401,24 @@ static irqreturn_t snd_vt1724_interrupt(int irq, void *dev_id)
                status &= status_mask;
                if (status == 0)
                        break;
+               spin_lock(&ice->reg_lock);
                if (++timeout > 10) {
                        status = inb(ICEREG1724(ice, IRQSTAT));
                        printk(KERN_ERR "ice1724: Too long irq loop, "
                               "status = 0x%x\n", status);
                        if (status & VT1724_IRQ_MPU_TX) {
                                printk(KERN_ERR "ice1724: Disabling MPU_TX\n");
-                               outb(inb(ICEREG1724(ice, IRQMASK)) |
-                                    VT1724_IRQ_MPU_TX,
-                                    ICEREG1724(ice, IRQMASK));
+                               enable_midi_irq(ice, VT1724_IRQ_MPU_TX, 0);
                        }
+                       spin_unlock(&ice->reg_lock);
                        break;
                }
                handled = 1;
                if (status & VT1724_IRQ_MPU_TX) {
-                       spin_lock(&ice->reg_lock);
                        if (ice->midi_output)
                                vt1724_midi_write(ice);
-                       spin_unlock(&ice->reg_lock);
+                       else
+                               enable_midi_irq(ice, VT1724_IRQ_MPU_TX, 0);
                        /* Due to mysterical reasons, MPU_TX is always
                         * generated (and can't be cleared) when a PCM
                         * playback is going.  So let's ignore at the
@@ -415,15 +427,14 @@ static irqreturn_t snd_vt1724_interrupt(int irq, void *dev_id)
                        status_mask &= ~VT1724_IRQ_MPU_TX;
                }
                if (status & VT1724_IRQ_MPU_RX) {
-                       spin_lock(&ice->reg_lock);
                        if (ice->midi_input)
                                vt1724_midi_read(ice);
                        else
                                vt1724_midi_clear_rx(ice);
-                       spin_unlock(&ice->reg_lock);
                }
                /* ack MPU irq */
                outb(status, ICEREG1724(ice, IRQSTAT));
+               spin_unlock(&ice->reg_lock);
                if (status & VT1724_IRQ_MTPCM) {
                        /*
                         * Multi-track PCM