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[PATCH] Au1550 AC'97 OSS driver spinlock fixes 

We have found some issues with Au1550 AC'97 OSS driver in 2.6
(sound/oss/au1550_ac97.c), though it also should concern 2.4 driver
(drivers/sound/au1550_psc.c).

start_dac() grabs a spinlock already held by its caller, au1550_write().
This doesn't show up with the standard UP spinlock impelmentation but when
the different one (mutex based) is in use, a lockup happens.

And the interrupt handlers also didn't grab the spinlock -- that's OK in
the usual kernel but not when the IRQ handlers are threaded.  So, they're
grabbing the spinlock now (as every correct interrupt handler should do).

Signed-off-by: Konstantin Baidarov <kbaidarov@ru.mvista.com>
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Sergei Shtylylov 2005-12-15 12:34:30 -08:00 committed by Linus Torvalds
parent 2f40fb72a2
commit 7b6666530e
1 changed files with 18 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
sound/oss/au1550_ac97.c
View File

@ -578,17 +578,15 @@ set_recv_slots(int num_channels)
} while ((stat & PSC_AC97STAT_DR) == 0);
}
/* Hold spinlock for both start_dac() and start_adc() calls */
static void
start_dac(struct au1550_state *s)
{
struct dmabuf *db = &s->dma_dac;
unsigned long flags;
if (!db->stopped)
return;
spin_lock_irqsave(&s->lock, flags);
set_xmit_slots(db->num_channels);
au_writel(PSC_AC97PCR_TC, PSC_AC97PCR);
au_sync();
@ -598,8 +596,6 @@ start_dac(struct au1550_state *s)
au1xxx_dbdma_start(db->dmanr);
db->stopped = 0;
spin_unlock_irqrestore(&s->lock, flags);
}
static void
@ -718,7 +714,6 @@ prog_dmabuf_dac(struct au1550_state *s)
}
/* hold spinlock for the following */
static void
dac_dma_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
@ -726,6 +721,8 @@ dac_dma_interrupt(int irq, void *dev_id, struct pt_regs *regs)
struct dmabuf *db = &s->dma_dac;
u32 ac97c_stat;
spin_lock(&s->lock);
ac97c_stat = au_readl(PSC_AC97STAT);
if (ac97c_stat & (AC97C_XU | AC97C_XO | AC97C_TE))
pr_debug("AC97C status = 0x%08x\n", ac97c_stat);
@ -747,6 +744,8 @@ dac_dma_interrupt(int irq, void *dev_id, struct pt_regs *regs)
/* wake up anybody listening */
if (waitqueue_active(&db->wait))
wake_up(&db->wait);
spin_unlock(&s->lock);
}
@ -758,6 +757,8 @@ adc_dma_interrupt(int irq, void *dev_id, struct pt_regs *regs)
u32 obytes;
char *obuf;
spin_lock(&s->lock);
/* Pull the buffer from the dma queue.
*/
au1xxx_dbdma_get_dest(dp->dmanr, (void *)(&obuf), &obytes);
@ -765,6 +766,7 @@ adc_dma_interrupt(int irq, void *dev_id, struct pt_regs *regs)
if ((dp->count + obytes) > dp->dmasize) {
/* Overrun. Stop ADC and log the error
*/
spin_unlock(&s->lock);
stop_adc(s);
dp->error++;
err("adc overrun");
@ -787,6 +789,7 @@ adc_dma_interrupt(int irq, void *dev_id, struct pt_regs *regs)
if (waitqueue_active(&dp->wait))
wake_up(&dp->wait);
spin_unlock(&s->lock);
}
static loff_t
@ -1048,9 +1051,9 @@ au1550_read(struct file *file, char *buffer, size_t count, loff_t *ppos)
/* wait for samples in ADC dma buffer
*/
do {
spin_lock_irqsave(&s->lock, flags);
if (db->stopped)
start_adc(s);
spin_lock_irqsave(&s->lock, flags);
avail = db->count;
if (avail <= 0)
__set_current_state(TASK_INTERRUPTIBLE);
@ -1570,15 +1573,19 @@ au1550_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
if (get_user(val, (int *) arg))
return -EFAULT;
if (file->f_mode & FMODE_READ) {
if (val & PCM_ENABLE_INPUT)
if (val & PCM_ENABLE_INPUT) {
spin_lock_irqsave(&s->lock, flags);
start_adc(s);
else
spin_unlock_irqrestore(&s->lock, flags);
} else
stop_adc(s);
}
if (file->f_mode & FMODE_WRITE) {
if (val & PCM_ENABLE_OUTPUT)
if (val & PCM_ENABLE_OUTPUT) {
spin_lock_irqsave(&s->lock, flags);
start_dac(s);
else
spin_unlock_irqrestore(&s->lock, flags);
} else
stop_dac(s);
}
return 0;