Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into for-linus-1

* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6: (9356 commits)
  [media] rc: update for bitop name changes
  fs: simplify iget & friends
  fs: pull inode->i_lock up out of writeback_single_inode
  fs: rename inode_lock to inode_hash_lock
  fs: move i_wb_list out from under inode_lock
  fs: move i_sb_list out from under inode_lock
  fs: remove inode_lock from iput_final and prune_icache
  fs: Lock the inode LRU list separately
  fs: factor inode disposal
  fs: protect inode->i_state with inode->i_lock
  lib, arch: add filter argument to show_mem and fix private implementations
  SLUB: Write to per cpu data when allocating it
  slub: Fix debugobjects with lockless fastpath
  autofs4: Do not potentially dereference NULL pointer returned by fget() in autofs_dev_ioctl_setpipefd()
  autofs4 - remove autofs4_lock
  autofs4 - fix d_manage() return on rcu-walk
  autofs4 - fix autofs4_expire_indirect() traversal
  autofs4 - fix dentry leak in autofs4_expire_direct()
  autofs4 - reinstate last used update on access
  vfs - check non-mountpoint dentry might block in __follow_mount_rcu()
  ...

NOTE!

This merge commit was created to fix compilation error. The block
tree was merged upstream and removed the 'elv_queue_empty()'
function which the new 'mtdswap' driver is using. So a simple
merge of the mtd tree with upstream does not compile. And the
mtd tree has already be published, so re-basing it is not an option.

To fix this unfortunate situation, I had to merge upstream into the
mtd-2.6.git tree without committing, put the fixup patch on top of
this, and then commit this. The result is that we do not have commits
which do not compile.

In other words, this merge commit "merges" 3 things: the MTD tree, the
upstream tree, and the fixup patch.

2 files changed, 169 insertions, 181 deletions

diff --git a/sound/arm/aaci.c b/sound/arm/aaci.c
index 91acc9a243e..d0cead38d5f 100644
--- a/sound/arm/aaci.c
+++ b/sound/arm/aaci.c
@@ -30,6 +30,8 @@
 
 #define DRIVER_NAME	"aaci-pl041"
 
+#define FRAME_PERIOD_US	21
+
 /*
  * PM support is not complete.  Turn it off.
  */
@@ -48,7 +50,11 @@ static void aaci_ac97_select_codec(struct aaci *aaci, struct snd_ac97 *ac97)
 	if (v & SLFR_1RXV)
 		readl(aaci->base + AACI_SL1RX);
 
-	writel(maincr, aaci->base + AACI_MAINCR);
+	if (maincr != readl(aaci->base + AACI_MAINCR)) {
+		writel(maincr, aaci->base + AACI_MAINCR);
+		readl(aaci->base + AACI_MAINCR);
+		udelay(1);
+	}
 }
 
 /*
@@ -64,8 +70,8 @@ static void aaci_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
 			    unsigned short val)
 {
 	struct aaci *aaci = ac97->private_data;
+	int timeout;
 	u32 v;
-	int timeout = 5000;
 
 	if (ac97->num >= 4)
 		return;
@@ -81,14 +87,17 @@ static void aaci_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
 	writel(val << 4, aaci->base + AACI_SL2TX);
 	writel(reg << 12, aaci->base + AACI_SL1TX);
 
-	/*
-	 * Wait for the transmission of both slots to complete.
-	 */
+	/* Initially, wait one frame period */
+	udelay(FRAME_PERIOD_US);
+
+	/* And then wait an additional eight frame periods for it to be sent */
+	timeout = FRAME_PERIOD_US * 8;
 	do {
+		udelay(1);
 		v = readl(aaci->base + AACI_SLFR);
 	} while ((v & (SLFR_1TXB|SLFR_2TXB)) && --timeout);
 
-	if (!timeout)
+	if (v & (SLFR_1TXB|SLFR_2TXB))
 		dev_err(&aaci->dev->dev,
 			"timeout waiting for write to complete\n");
 
@@ -101,9 +110,8 @@ static void aaci_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
 static unsigned short aaci_ac97_read(struct snd_ac97 *ac97, unsigned short reg)
 {
 	struct aaci *aaci = ac97->private_data;
+	int timeout, retries = 10;
 	u32 v;
-	int timeout = 5000;
-	int retries = 10;
 
 	if (ac97->num >= 4)
 		return ~0;
@@ -117,35 +125,34 @@ static unsigned short aaci_ac97_read(struct snd_ac97 *ac97, unsigned short reg)
 	 */
 	writel((reg << 12) | (1 << 19), aaci->base + AACI_SL1TX);
 
-	/*
-	 * Wait for the transmission to complete.
-	 */
+	/* Initially, wait one frame period */
+	udelay(FRAME_PERIOD_US);
+
+	/* And then wait an additional eight frame periods for it to be sent */
+	timeout = FRAME_PERIOD_US * 8;
 	do {
+		udelay(1);
 		v = readl(aaci->base + AACI_SLFR);
 	} while ((v & SLFR_1TXB) && --timeout);
 
-	if (!timeout) {
+	if (v & SLFR_1TXB) {
 		dev_err(&aaci->dev->dev, "timeout on slot 1 TX busy\n");
 		v = ~0;
 		goto out;
 	}
 
-	/*
-	 * Give the AC'97 codec more than enough time
-	 * to respond. (42us = ~2 frames at 48kHz.)
-	 */
-	udelay(42);
+	/* Now wait for the response frame */
+	udelay(FRAME_PERIOD_US);
 
-	/*
-	 * Wait for slot 2 to indicate data.
-	 */
-	timeout = 5000;
+	/* And then wait an additional eight frame periods for data */
+	timeout = FRAME_PERIOD_US * 8;
 	do {
+		udelay(1);
 		cond_resched();
 		v = readl(aaci->base + AACI_SLFR) & (SLFR_1RXV|SLFR_2RXV);
 	} while ((v != (SLFR_1RXV|SLFR_2RXV)) && --timeout);
 
-	if (!timeout) {
+	if (v != (SLFR_1RXV|SLFR_2RXV)) {
 		dev_err(&aaci->dev->dev, "timeout on RX valid\n");
 		v = ~0;
 		goto out;
@@ -179,6 +186,7 @@ aaci_chan_wait_ready(struct aaci_runtime *aacirun, unsigned long mask)
 	int timeout = 5000;
 
 	do {
+		udelay(1);
 		val = readl(aacirun->base + AACI_SR);
 	} while (val & mask && timeout--);
 }
@@ -202,6 +210,7 @@ static void aaci_fifo_irq(struct aaci *aaci, int channel, u32 mask)
 
 	if (mask & ISR_RXINTR) {
 		struct aaci_runtime *aacirun = &aaci->capture;
+		bool period_elapsed = false;
 		void *ptr;
 
 		if (!aacirun->substream || !aacirun->start) {
@@ -214,15 +223,12 @@ static void aaci_fifo_irq(struct aaci *aaci, int channel, u32 mask)
 
 		ptr = aacirun->ptr;
 		do {
-			unsigned int len = aacirun->fifosz;
+			unsigned int len = aacirun->fifo_bytes;
 			u32 val;
 
 			if (aacirun->bytes <= 0) {
 				aacirun->bytes += aacirun->period;
-				aacirun->ptr = ptr;
-				spin_unlock(&aacirun->lock);
-				snd_pcm_period_elapsed(aacirun->substream);
-				spin_lock(&aacirun->lock);
+				period_elapsed = true;
 			}
 			if (!(aacirun->cr & CR_EN))
 				break;
@@ -252,6 +258,9 @@ static void aaci_fifo_irq(struct aaci *aaci, int channel, u32 mask)
 		aacirun->ptr = ptr;
 
 		spin_unlock(&aacirun->lock);
+
+		if (period_elapsed)
+			snd_pcm_period_elapsed(aacirun->substream);
 	}
 
 	if (mask & ISR_URINTR) {
@@ -261,6 +270,7 @@ static void aaci_fifo_irq(struct aaci *aaci, int channel, u32 mask)
 
 	if (mask & ISR_TXINTR) {
 		struct aaci_runtime *aacirun = &aaci->playback;
+		bool period_elapsed = false;
 		void *ptr;
 
 		if (!aacirun->substream || !aacirun->start) {
@@ -273,15 +283,12 @@ static void aaci_fifo_irq(struct aaci *aaci, int channel, u32 mask)
 
 		ptr = aacirun->ptr;
 		do {
-			unsigned int len = aacirun->fifosz;
+			unsigned int len = aacirun->fifo_bytes;
 			u32 val;
 
 			if (aacirun->bytes <= 0) {
 				aacirun->bytes += aacirun->period;
-				aacirun->ptr = ptr;
-				spin_unlock(&aacirun->lock);
-				snd_pcm_period_elapsed(aacirun->substream);
-				spin_lock(&aacirun->lock);
+				period_elapsed = true;
 			}
 			if (!(aacirun->cr & CR_EN))
 				break;
@@ -311,6 +318,9 @@ static void aaci_fifo_irq(struct aaci *aaci, int channel, u32 mask)
 		aacirun->ptr = ptr;
 
 		spin_unlock(&aacirun->lock);
+
+		if (period_elapsed)
+			snd_pcm_period_elapsed(aacirun->substream);
 	}
 }
 
@@ -353,7 +363,7 @@ static struct snd_pcm_hardware aaci_hw_info = {
 
 	/* rates are setup from the AC'97 codec */
 	.channels_min		= 2,
-	.channels_max		= 6,
+	.channels_max		= 2,
 	.buffer_bytes_max	= 64 * 1024,
 	.period_bytes_min	= 256,
 	.period_bytes_max	= PAGE_SIZE,
@@ -361,12 +371,46 @@ static struct snd_pcm_hardware aaci_hw_info = {
 	.periods_max		= PAGE_SIZE / 16,
 };
 
-static int __aaci_pcm_open(struct aaci *aaci,
-			   struct snd_pcm_substream *substream,
-			   struct aaci_runtime *aacirun)
+/*
+ * We can support two and four channel audio.  Unfortunately
+ * six channel audio requires a non-standard channel ordering:
+ *   2 -> FL(3), FR(4)
+ *   4 -> FL(3), FR(4), SL(7), SR(8)
+ *   6 -> FL(3), FR(4), SL(7), SR(8), C(6), LFE(9) (required)
+ *        FL(3), FR(4), C(6), SL(7), SR(8), LFE(9) (actual)
+ * This requires an ALSA configuration file to correct.
+ */
+static int aaci_rule_channels(struct snd_pcm_hw_params *p,
+	struct snd_pcm_hw_rule *rule)
+{
+	static unsigned int channel_list[] = { 2, 4, 6 };
+	struct aaci *aaci = rule->private;
+	unsigned int mask = 1 << 0, slots;
+
+	/* pcms[0] is the our 5.1 PCM instance. */
+	slots = aaci->ac97_bus->pcms[0].r[0].slots;
+	if (slots & (1 << AC97_SLOT_PCM_SLEFT)) {
+		mask |= 1 << 1;
+		if (slots & (1 << AC97_SLOT_LFE))
+			mask |= 1 << 2;
+	}
+
+	return snd_interval_list(hw_param_interval(p, rule->var),
+				 ARRAY_SIZE(channel_list), channel_list, mask);
+}
+
+static int aaci_pcm_open(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
-	int ret;
+	struct aaci *aaci = substream->private_data;
+	struct aaci_runtime *aacirun;
+	int ret = 0;
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		aacirun = &aaci->playback;
+	} else {
+		aacirun = &aaci->capture;
+	}
 
 	aacirun->substream = substream;
 	runtime->private_data = aacirun;
@@ -374,27 +418,37 @@ static int __aaci_pcm_open(struct aaci *aaci,
 	runtime->hw.rates = aacirun->pcm->rates;
 	snd_pcm_limit_hw_rates(runtime);
 
-	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
-	    aacirun->pcm->r[1].slots)
-		snd_ac97_pcm_double_rate_rules(runtime);
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		runtime->hw.channels_max = 6;
+
+		/* Add rule describing channel dependency. */
+		ret = snd_pcm_hw_rule_add(substream->runtime, 0,
+					  SNDRV_PCM_HW_PARAM_CHANNELS,
+					  aaci_rule_channels, aaci,
+					  SNDRV_PCM_HW_PARAM_CHANNELS, -1);
+		if (ret)
+			return ret;
+
+		if (aacirun->pcm->r[1].slots)
+			snd_ac97_pcm_double_rate_rules(runtime);
+	}
 
 	/*
-	 * FIXME: ALSA specifies fifo_size in bytes.  If we're in normal
-	 * mode, each 32-bit word contains one sample.  If we're in
-	 * compact mode, each 32-bit word contains two samples, effectively
-	 * halving the FIFO size.  However, we don't know for sure which
-	 * we'll be using at this point.  We set this to the lower limit.
+	 * ALSA wants the byte-size of the FIFOs.  As we only support
+	 * 16-bit samples, this is twice the FIFO depth irrespective
+	 * of whether it's in compact mode or not.
 	 */
-	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;
+	runtime->hw.fifo_size = aaci->fifo_depth * 2;
+
+	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;
 }
 
@@ -410,7 +464,11 @@ 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;
 }
@@ -436,12 +494,21 @@ static int aaci_pcm_hw_free(struct snd_pcm_substream *substream)
 	return 0;
 }
 
+/* Channel to slot mask */
+static const u32 channels_to_slotmask[] = {
+	[2] = CR_SL3 | CR_SL4,
+	[4] = CR_SL3 | CR_SL4 | CR_SL7 | CR_SL8,
+	[6] = CR_SL3 | CR_SL4 | CR_SL7 | CR_SL8 | CR_SL6 | CR_SL9,
+};
+
 static int aaci_pcm_hw_params(struct snd_pcm_substream *substream,
-			      struct aaci_runtime *aacirun,
 			      struct snd_pcm_hw_params *params)
 {
+	struct aaci_runtime *aacirun = substream->runtime->private_data;
+	unsigned int channels = params_channels(params);
+	unsigned int rate = params_rate(params);
+	int dbl = rate > 48000;
 	int err;
-	struct aaci *aaci = substream->private_data;
 
 	aaci_pcm_hw_free(substream);
 	if (aacirun->pcm_open) {
@@ -449,22 +516,28 @@ static int aaci_pcm_hw_params(struct snd_pcm_substream *substream,
 		aacirun->pcm_open = 0;
 	}
 
+	/* channels is already limited to 2, 4, or 6 by aaci_rule_channels */
+	if (dbl && channels != 2)
+		return -EINVAL;
+
 	err = snd_pcm_lib_malloc_pages(substream,
 				       params_buffer_bytes(params));
 	if (err >= 0) {
-		unsigned int rate = params_rate(params);
-		int dbl = rate > 48000;
+		struct aaci *aaci = substream->private_data;
 
-		err = snd_ac97_pcm_open(aacirun->pcm, rate,
-					params_channels(params),
+		err = snd_ac97_pcm_open(aacirun->pcm, rate, channels,
 					aacirun->pcm->r[dbl].slots);
 
 		aacirun->pcm_open = err == 0;
 		aacirun->cr = CR_FEN | CR_COMPACT | CR_SZ16;
-		aacirun->fifosz = aaci->fifosize * 4;
-
-		if (aacirun->cr & CR_COMPACT)
-			aacirun->fifosz >>= 1;
+		aacirun->cr |= channels_to_slotmask[channels + dbl * 2];
+
+		/*
+		 * fifo_bytes is the number of bytes we transfer to/from
+		 * the FIFO, including padding.  So that's x4.  As we're
+		 * in compact mode, the FIFO is half the size.
+		 */
+		aacirun->fifo_bytes = aaci->fifo_depth * 4 / 2;
 	}
 
 	return err;
@@ -475,11 +548,11 @@ static int aaci_pcm_prepare(struct snd_pcm_substream *substream)
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct aaci_runtime *aacirun = runtime->private_data;
 
+	aacirun->period	= snd_pcm_lib_period_bytes(substream);
 	aacirun->start	= runtime->dma_area;
 	aacirun->end	= aacirun->start + snd_pcm_lib_buffer_bytes(substream);
 	aacirun->ptr	= aacirun->start;
-	aacirun->period	=
-	aacirun->bytes	= frames_to_bytes(runtime, runtime->period_size);
+	aacirun->bytes	= aacirun->period;
 
 	return 0;
 }
@@ -497,89 +570,6 @@ static snd_pcm_uframes_t aaci_pcm_pointer(struct snd_pcm_substream *substream)
 /*
  * Playback specific ALSA stuff
  */
-static const u32 channels_to_txmask[] = {
-	[2] = CR_SL3 | CR_SL4,
-	[4] = CR_SL3 | CR_SL4 | CR_SL7 | CR_SL8,
-	[6] = CR_SL3 | CR_SL4 | CR_SL7 | CR_SL8 | CR_SL6 | CR_SL9,
-};
-
-/*
- * We can support two and four channel audio.  Unfortunately
- * six channel audio requires a non-standard channel ordering:
- *   2 -> FL(3), FR(4)
- *   4 -> FL(3), FR(4), SL(7), SR(8)
- *   6 -> FL(3), FR(4), SL(7), SR(8), C(6), LFE(9) (required)
- *        FL(3), FR(4), C(6), SL(7), SR(8), LFE(9) (actual)
- * This requires an ALSA configuration file to correct.
- */
-static unsigned int channel_list[] = { 2, 4, 6 };
-
-static int
-aaci_rule_channels(struct snd_pcm_hw_params *p, struct snd_pcm_hw_rule *rule)
-{
-	struct aaci *aaci = rule->private;
-	unsigned int chan_mask = 1 << 0, slots;
-
-	/*
-	 * pcms[0] is the our 5.1 PCM instance.
-	 */
-	slots = aaci->ac97_bus->pcms[0].r[0].slots;
-	if (slots & (1 << AC97_SLOT_PCM_SLEFT)) {
-		chan_mask |= 1 << 1;
-		if (slots & (1 << AC97_SLOT_LFE))
-			chan_mask |= 1 << 2;
-	}
-
-	return snd_interval_list(hw_param_interval(p, rule->var),
-				 ARRAY_SIZE(channel_list), channel_list,
-				 chan_mask);
-}
-
-static int aaci_pcm_open(struct snd_pcm_substream *substream)
-{
-	struct aaci *aaci = substream->private_data;
-	int ret;
-
-	/*
-	 * Add rule describing channel dependency.
-	 */
-	ret = snd_pcm_hw_rule_add(substream->runtime, 0,
-				  SNDRV_PCM_HW_PARAM_CHANNELS,
-				  aaci_rule_channels, aaci,
-				  SNDRV_PCM_HW_PARAM_CHANNELS, -1);
-	if (ret)
-		return ret;
-
-	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
-		ret = __aaci_pcm_open(aaci, substream, &aaci->playback);
-	} else {
-		ret = __aaci_pcm_open(aaci, substream, &aaci->capture);
-	}
-	return ret;
-}
-
-static int aaci_pcm_playback_hw_params(struct snd_pcm_substream *substream,
-				       struct snd_pcm_hw_params *params)
-{
-	struct aaci_runtime *aacirun = substream->runtime->private_data;
-	unsigned int channels = params_channels(params);
-	int ret;
-
-	WARN_ON(channels >= ARRAY_SIZE(channels_to_txmask) ||
-		!channels_to_txmask[channels]);
-
-	ret = aaci_pcm_hw_params(substream, aacirun, params);
-
-	/*
-	 * Enable FIFO, compact mode, 16 bits per sample.
-	 * FIXME: double rate slots?
-	 */
-	if (ret >= 0)
-		aacirun->cr |= channels_to_txmask[channels];
-
-	return ret;
-}
-
 static void aaci_pcm_playback_stop(struct aaci_runtime *aacirun)
 {
 	u32 ie;
@@ -649,27 +639,13 @@ static struct snd_pcm_ops aaci_playback_ops = {
 	.open		= aaci_pcm_open,
 	.close		= aaci_pcm_close,
 	.ioctl		= snd_pcm_lib_ioctl,
-	.hw_params	= aaci_pcm_playback_hw_params,
+	.hw_params	= aaci_pcm_hw_params,
 	.hw_free	= aaci_pcm_hw_free,
 	.prepare	= aaci_pcm_prepare,
 	.trigger	= aaci_pcm_playback_trigger,
 	.pointer	= aaci_pcm_pointer,
 };
 
-static int aaci_pcm_capture_hw_params(struct snd_pcm_substream *substream,
-				      struct snd_pcm_hw_params *params)
-{
-	struct aaci_runtime *aacirun = substream->runtime->private_data;
-	int ret;
-
-	ret = aaci_pcm_hw_params(substream, aacirun, params);
-	if (ret >= 0)
-		/* Line in record: slot 3 and 4 */
-		aacirun->cr |= CR_SL3 | CR_SL4;
-
-	return ret;
-}
-
 static void aaci_pcm_capture_stop(struct aaci_runtime *aacirun)
 {
 	u32 ie;
@@ -766,7 +742,7 @@ static struct snd_pcm_ops aaci_capture_ops = {
 	.open		= aaci_pcm_open,
 	.close		= aaci_pcm_close,
 	.ioctl		= snd_pcm_lib_ioctl,
-	.hw_params	= aaci_pcm_capture_hw_params,
+	.hw_params	= aaci_pcm_hw_params,
 	.hw_free	= aaci_pcm_hw_free,
 	.prepare	= aaci_pcm_capture_prepare,
 	.trigger	= aaci_pcm_capture_trigger,
@@ -874,7 +850,7 @@ static int __devinit aaci_probe_ac97(struct aaci *aaci)
 	 * Give the AC'97 codec more than enough time
 	 * to wake up. (42us = ~2 frames at 48kHz.)
 	 */
-	udelay(42);
+	udelay(FRAME_PERIOD_US * 2);
 
 	ret = snd_ac97_bus(aaci->card, 0, &aaci_bus_ops, aaci, &ac97_bus);
 	if (ret)
@@ -933,12 +909,13 @@ static struct aaci * __devinit aaci_init_card(struct amba_device *dev)
 	strlcpy(card->driver, DRIVER_NAME, sizeof(card->driver));
 	strlcpy(card->shortname, "ARM AC'97 Interface", sizeof(card->shortname));
 	snprintf(card->longname, sizeof(card->longname),
-		 "%s at 0x%016llx, irq %d",
-		 card->shortname, (unsigned long long)dev->res.start,
-		 dev->irq[0]);
+		 "%s PL%03x rev%u at 0x%08llx, irq %d",
+		 card->shortname, amba_part(dev), amba_rev(dev),
+		 (unsigned long long)dev->res.start, dev->irq[0]);
 
 	aaci = card->private_data;
 	mutex_init(&aaci->ac97_sem);
+	mutex_init(&aaci->irq_lock);
 	aaci->card = card;
 	aaci->dev = dev;
 
@@ -976,6 +953,10 @@ static unsigned int __devinit aaci_size_fifo(struct aaci *aaci)
 	struct aaci_runtime *aacirun = &aaci->playback;
 	int i;
 
+	/*
+	 * Enable the channel, but don't assign it to any slots, so
+	 * it won't empty onto the AC'97 link.
+	 */
 	writel(CR_FEN | CR_SZ16 | CR_EN, aacirun->base + AACI_TXCR);
 
 	for (i = 0; !(readl(aacirun->base + AACI_SR) & SR_TXFF) && i < 4096; i++)
@@ -989,10 +970,12 @@ static unsigned int __devinit aaci_size_fifo(struct aaci *aaci)
 	 * disabling the channel doesn't clear the FIFO.
 	 */
 	writel(aaci->maincr & ~MAINCR_IE, aaci->base + AACI_MAINCR);
+	readl(aaci->base + AACI_MAINCR);
+	udelay(1);
 	writel(aaci->maincr, aaci->base + AACI_MAINCR);
 
 	/*
-	 * If we hit 4096, we failed.  Go back to the specified
+	 * If we hit 4096 entries, we failed.  Go back to the specified
 	 * fifo depth.
 	 */
 	if (i == 4096)
@@ -1001,7 +984,8 @@ static unsigned int __devinit aaci_size_fifo(struct aaci *aaci)
 	return i;
 }
 
-static int __devinit aaci_probe(struct amba_device *dev, struct amba_id *id)
+static int __devinit aaci_probe(struct amba_device *dev,
+	const struct amba_id *id)
 {
 	struct aaci *aaci;
 	int ret, i;
@@ -1057,11 +1041,12 @@ static int __devinit aaci_probe(struct amba_device *dev, struct amba_id *id)
 
 	/*
 	 * Size the FIFOs (must be multiple of 16).
+	 * This is the number of entries in the FIFO.
 	 */
-	aaci->fifosize = aaci_size_fifo(aaci);
-	if (aaci->fifosize & 15) {
-		printk(KERN_WARNING "AACI: fifosize = %d not supported\n",
-		       aaci->fifosize);
+	aaci->fifo_depth = aaci_size_fifo(aaci);
+	if (aaci->fifo_depth & 15) {
+		printk(KERN_WARNING "AACI: FIFO depth %d not supported\n",
+		       aaci->fifo_depth);
 		ret = -ENODEV;
 		goto out;
 	}
@@ -1074,8 +1059,8 @@ static int __devinit aaci_probe(struct amba_device *dev, struct amba_id *id)
 
 	ret = snd_card_register(aaci->card);
 	if (ret == 0) {
-		dev_info(&dev->dev, "%s, fifo %d\n", aaci->card->longname,
-			 aaci->fifosize);
+		dev_info(&dev->dev, "%s\n", aaci->card->longname);
+		dev_info(&dev->dev, "FIFO %u entries\n", aaci->fifo_depth);
 		amba_set_drvdata(dev, aaci->card);
 		return ret;
 	}
diff --git a/sound/arm/aaci.h b/sound/arm/aaci.h
index 6a4a2eebdda..5791bd5bd2a 100644
--- a/sound/arm/aaci.h
+++ b/sound/arm/aaci.h
@@ -210,6 +210,8 @@ struct aaci_runtime {
 	u32			cr;
 	struct snd_pcm_substream	*substream;
 
+	unsigned int		period;	/* byte size of a "period" */
+
 	/*
 	 * PIO support
 	 */
@@ -217,15 +219,16 @@ struct aaci_runtime {
 	void			*end;
 	void			*ptr;
 	int			bytes;
-	unsigned int		period;
-	unsigned int		fifosz;
+	unsigned int		fifo_bytes;
 };
 
 struct aaci {
 	struct amba_device	*dev;
 	struct snd_card		*card;
 	void			__iomem *base;
-	unsigned int		fifosize;
+	unsigned int		fifo_depth;
+	unsigned int		users;
+	struct mutex		irq_lock;
 
 	/* AC'97 */
 	struct mutex		ac97_sem;