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[media] tm6000-alsa: fix some locking issues

Browse source 
Those locking issues affect tvtime, causing a kernel oops/panic, due to
a race condition.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Mauro Carvalho Chehab 2010-10-09 21:15:33 -03:00
parent dc961136b9
commit 06f08e3a4d
2 changed files with 40 additions and 9 deletions
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46
drivers/staging/tm6000/tm6000-alsa.c
View file

@ -201,6 +201,14 @@ static int snd_tm6000_pcm_open(struct snd_pcm_substream *substream)
*/
static int snd_tm6000_close(struct snd_pcm_substream *substream)
{
struct snd_tm6000_card *chip = snd_pcm_substream_chip(substream);
struct tm6000_core *core = chip->core;
if (atomic_read(&core->stream_started) > 0) {
atomic_set(&core->stream_started, 0);
schedule_work(&core->wq_trigger);
}
return 0;
}
@ -213,6 +221,9 @@ static int tm6000_fillbuf(struct tm6000_core *core, char *buf, int size)
unsigned int stride, buf_pos;
int length;
if (atomic_read(&core->stream_started) == 0)
return 0;
if (!size || !substream) {
dprintk(1, "substream was NULL\n");
return -EINVAL;
@ -298,8 +309,12 @@ static int snd_tm6000_hw_params(struct snd_pcm_substream *substream,
static int snd_tm6000_hw_free(struct snd_pcm_substream *substream)
{
struct snd_tm6000_card *chip = snd_pcm_substream_chip(substream);
struct tm6000_core *core = chip->core;
_tm6000_stop_audio_dma(chip);
if (atomic_read(&core->stream_started) > 0) {
atomic_set(&core->stream_started, 0);
schedule_work(&core->wq_trigger);
}
return 0;
}
@ -321,30 +336,42 @@ static int snd_tm6000_prepare(struct snd_pcm_substream *substream)
/*
* trigger callback
*/
static void audio_trigger(struct work_struct *work)
{
struct tm6000_core *core = container_of(work, struct tm6000_core,
wq_trigger);
struct snd_tm6000_card *chip = core->adev;
if (atomic_read(&core->stream_started)) {
dprintk(1, "starting capture");
_tm6000_start_audio_dma(chip);
} else {
dprintk(1, "stopping capture");
_tm6000_stop_audio_dma(chip);
}
}
static int snd_tm6000_card_trigger(struct snd_pcm_substream *substream, int cmd)
{
struct snd_tm6000_card *chip = snd_pcm_substream_chip(substream);
int err;
spin_lock(&chip->reg_lock);
struct tm6000_core *core = chip->core;
int err = 0;
switch (cmd) {
case SNDRV_PCM_TRIGGER_START:
err = _tm6000_start_audio_dma(chip);
atomic_set(&core->stream_started, 1);
break;
case SNDRV_PCM_TRIGGER_STOP:
err = _tm6000_stop_audio_dma(chip);
atomic_set(&core->stream_started, 0);
break;
default:
err = -EINVAL;
break;
}
spin_unlock(&chip->reg_lock);
schedule_work(&core->wq_trigger);
return err;
}
/*
* pointer callback
*/
@ -437,6 +464,7 @@ int tm6000_audio_init(struct tm6000_core *dev)
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_tm6000_pcm_ops);
INIT_WORK(&dev->wq_trigger, audio_trigger);
rc = snd_card_register(card);
if (rc < 0)
goto error;

3
drivers/staging/tm6000/tm6000.h
View file

@ -205,6 +205,9 @@ struct tm6000_core {
/* audio support */
struct snd_tm6000_card *adev;
struct work_struct wq_trigger; /* Trigger to start/stop audio for alsa module */
atomic_t stream_started; /* stream should be running if true */
struct tm6000_IR *ir;