From 7b6666530e2736f190a2629c8abe34275054449f Mon Sep 17 00:00:00 2001 From: Sergei Shtylylov Date: Thu, 15 Dec 2005 12:34:30 -0800 Subject: [PATCH] [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 Signed-off-by: Sergei Shtylyov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- sound/oss/au1550_ac97.c | 29 ++++++++++++++++++----------- 1 file changed, 18 insertions(+), 11 deletions(-) diff --git a/sound/oss/au1550_ac97.c b/sound/oss/au1550_ac97.c index 6b46a8a4b1..b963c550da 100644 --- a/sound/oss/au1550_ac97.c +++ b/sound/oss/au1550_ac97.c @@ -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; -- 2.39.5