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authorStas Sergeev <stsp@aknet.ru>2008-05-20 11:47:29 +0200
committerTakashi Iwai <tiwai@suse.de>2008-05-20 11:56:24 +0200
commit4b7afb0d0d23b298a7e6d30eaba0679449542d2e (patch)
treebeeff813fbb8d6dcffd13aefde4f43ccf9dc6f8e
parent8033c6e9736c29cce5f0d0abbca9a44dffb20c39 (diff)
snd-pcsp: use HRTIMER_CB_SOFTIRQ
Change HRTIMER_CB_IRQSAFE to HRTIMER_CB_SOFTIRQ, as suggested by Thomas Gleixner. That solves the lock dependancy reported in Bug #10701. That also allows to call hrtimer_start() directly, tasklet "stupid hack" removed. Signed-off-by: Stas Sergeev <stsp@aknet.ru> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Takashi Iwai <tiwai@suse.de>
-rw-r--r--sound/drivers/pcsp/pcsp.c2
-rw-r--r--sound/drivers/pcsp/pcsp_lib.c37
2 files changed, 5 insertions, 34 deletions
diff --git a/sound/drivers/pcsp/pcsp.c b/sound/drivers/pcsp/pcsp.c
index 54a1f9036c6..1899cf0685b 100644
--- a/sound/drivers/pcsp/pcsp.c
+++ b/sound/drivers/pcsp/pcsp.c
@@ -96,7 +96,7 @@ static int __devinit snd_card_pcsp_probe(int devnum, struct device *dev)
return -EINVAL;
hrtimer_init(&pcsp_chip.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
- pcsp_chip.timer.cb_mode = HRTIMER_CB_IRQSAFE;
+ pcsp_chip.timer.cb_mode = HRTIMER_CB_SOFTIRQ;
pcsp_chip.timer.function = pcsp_do_timer;
card = snd_card_new(index, id, THIS_MODULE, 0);
diff --git a/sound/drivers/pcsp/pcsp_lib.c b/sound/drivers/pcsp/pcsp_lib.c
index 7ad4a1534b2..e341f3f83b6 100644
--- a/sound/drivers/pcsp/pcsp_lib.c
+++ b/sound/drivers/pcsp/pcsp_lib.c
@@ -9,7 +9,6 @@
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <sound/pcm.h>
-#include <linux/interrupt.h>
#include <asm/io.h>
#include "pcsp.h"
@@ -20,34 +19,8 @@ MODULE_PARM_DESC(nforce_wa, "Apply NForce chipset workaround "
#define DMIX_WANTS_S16 1
-static void pcsp_start_timer(unsigned long dummy)
-{
- hrtimer_start(&pcsp_chip.timer, ktime_set(0, 0), HRTIMER_MODE_REL);
-}
-
-/*
- * We need the hrtimer_start as a tasklet to avoid
- * the nasty locking problem. :(
- * The problem:
- * - The timer handler is called with the cpu_base->lock
- * already held by hrtimer code.
- * - snd_pcm_period_elapsed() takes the
- * substream->self_group.lock.
- * So far so good.
- * But the snd_pcsp_trigger() is called with the
- * substream->self_group.lock held, and it calls
- * hrtimer_start(), which takes the cpu_base->lock.
- * You see the problem. We have the code pathes
- * which take two locks in a reverse order. This
- * can deadlock and the lock validator complains.
- * The only solution I could find was to move the
- * hrtimer_start() into a tasklet. -stsp
- */
-static DECLARE_TASKLET(pcsp_start_timer_tasklet, pcsp_start_timer, 0);
-
enum hrtimer_restart pcsp_do_timer(struct hrtimer *handle)
{
- unsigned long flags;
unsigned char timer_cnt, val;
int fmt_size, periods_elapsed;
u64 ns;
@@ -66,9 +39,7 @@ enum hrtimer_restart pcsp_do_timer(struct hrtimer *handle)
return HRTIMER_RESTART;
}
- /* hrtimer calls us from both hardirq and softirq contexts,
- * so irqsave :( */
- spin_lock_irqsave(&chip->substream_lock, flags);
+ spin_lock_irq(&chip->substream_lock);
/* Takashi Iwai says regarding this extra lock:
If the irq handler handles some data on the DMA buffer, it should
@@ -139,7 +110,7 @@ enum hrtimer_restart pcsp_do_timer(struct hrtimer *handle)
chip->period_ptr %= buffer_bytes;
}
- spin_unlock_irqrestore(&chip->substream_lock, flags);
+ spin_unlock_irq(&chip->substream_lock);
if (!atomic_read(&chip->timer_active))
return HRTIMER_NORESTART;
@@ -153,7 +124,7 @@ enum hrtimer_restart pcsp_do_timer(struct hrtimer *handle)
exit_nr_unlock2:
snd_pcm_stream_unlock(substream);
exit_nr_unlock1:
- spin_unlock_irqrestore(&chip->substream_lock, flags);
+ spin_unlock_irq(&chip->substream_lock);
return HRTIMER_NORESTART;
}
@@ -174,7 +145,7 @@ static void pcsp_start_playing(struct snd_pcsp *chip)
atomic_set(&chip->timer_active, 1);
chip->thalf = 0;
- tasklet_schedule(&pcsp_start_timer_tasklet);
+ hrtimer_start(&pcsp_chip.timer, ktime_set(0, 0), HRTIMER_MODE_REL);
}
static void pcsp_stop_playing(struct snd_pcsp *chip)