[ALSA] rtctimer: handle RTC interrupts with a tasklet

The calls to rtc_control() from inside the interrupt handler can upset
the RTC code, so move our interrupt handling code to a tasklet.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 14 insertions, 6 deletions

diff --git a/sound/core/rtctimer.c b/sound/core/rtctimer.c
index 412dd62b654e..9f7b32e1ccde 100644
--- a/sound/core/rtctimer.c
+++ b/sound/core/rtctimer.c
@@ -22,13 +22,10 @@
 
 #include <sound/driver.h>
 #include <linux/init.h>
-#include <linux/time.h>
-#include <linux/threads.h>
 #include <linux/interrupt.h>
 #include <linux/moduleparam.h>
 #include <sound/core.h>
 #include <sound/timer.h>
-#include <sound/info.h>
 
 #if defined(CONFIG_RTC) || defined(CONFIG_RTC_MODULE)
 
@@ -50,7 +47,9 @@ static int rtctimer_stop(struct snd_timer *t);
  * The hardware dependent description for this timer.
  */
 static struct snd_timer_hardware rtc_hw = {
-        .flags =        SNDRV_TIMER_HW_FIRST|SNDRV_TIMER_HW_AUTO,
+        .flags =        SNDRV_TIMER_HW_AUTO |
+                        SNDRV_TIMER_HW_FIRST |
+                        SNDRV_TIMER_HW_TASKLET,
         .ticks =        100000000L,             /* FIXME: XXX */
         .open =         rtctimer_open,
         .close =        rtctimer_close,
@@ -60,6 +59,7 @@ static struct snd_timer_hardware rtc_hw = {
 
 static int rtctimer_freq = RTC_FREQ;            /* frequency */
 static struct snd_timer *rtctimer;
+static struct tasklet_struct rtc_tasklet;
 static rtc_task_t rtc_task;
 
 
@@ -81,6 +81,7 @@ rtctimer_close(struct snd_timer *t)
         rtc_task_t *rtc = t->private_data;
         if (rtc) {
                 rtc_unregister(rtc);
+                tasklet_kill(&rtc_tasklet);
                 t->private_data = NULL;
         }
         return 0;
@@ -105,12 +106,17 @@ rtctimer_stop(struct snd_timer *timer)
         return 0;
 }
 
+static void rtctimer_tasklet(unsigned long data)
+{
+        snd_timer_interrupt((struct snd_timer *)data, 1);
+}
+
 /*
  * interrupt
  */
 static void rtctimer_interrupt(void *private_data)
 {
-        snd_timer_interrupt(private_data, 1);
+        tasklet_hi_schedule(private_data);
 }
 
 
@@ -139,9 +145,11 @@ static int __init rtctimer_init(void)
         timer->hw = rtc_hw;
         timer->hw.resolution = NANO_SEC / rtctimer_freq;
 
+        tasklet_init(&rtc_tasklet, rtctimer_tasklet, (unsigned long)timer);
+
         /* set up RTC callback */
         rtc_task.func = rtctimer_interrupt;
-        rtc_task.private_data = timer;
+        rtc_task.private_data = &rtc_tasklet;
 
         err = snd_timer_global_register(timer);
         if (err < 0) {