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authorOskar Schirmer <oskar@scara.com>2013-11-12 15:46:38 +0000
committerMark Brown <broonie@linaro.org>2013-11-14 12:59:44 +0000
commitfc7dc61d9a87011aaf8a6eb3144ebf9552adf5d2 (patch)
tree4d6e4007b7fd6bd144fadd4ef01390728304876d /sound
parent71d0c3a876e007f68fc2ed433119dd4f4dc408a7 (diff)
ASoC: fsl: imx-pcm-fiq: omit fiq counter to avoid harm in unbalanced situations
Unbalanced calls to snd_imx_pcm_trigger() may result in endless FIQ activity and thus provoke eternal sound. While on the first glance, the switch statement looks pretty symmetric, the SUSPEND/RESUME pair is not: the suspend case comes along snd_pcm_suspend_all(), which for fsl/imx-pcm-fiq is called only at snd_soc_suspend(), but the resume case originates straight from the SNDRV_PCM_IOCTL_RESUME. This way userland may provoke an unbalanced resume, which might cause the fiq_enable counter to increase and never return to zero again, so eventually imx_pcm_fiq is never disabled. Simply removing the fiq_enable will solve the problem, as long as one never goes play and capture game simultaneously, but beware trying both at once, the early TRIGGER_STOP will cut off the other activity prematurely. So now playing and capturing is scrutinized separately, instead of by counting. Signed-off-by: Oskar Schirmer <oskar@scara.com> Signed-off-by: Mark Brown <broonie@linaro.org> Cc: stable@vger.kernel.org
Diffstat (limited to 'sound')
-rw-r--r--sound/soc/fsl/imx-pcm-fiq.c29
1 files changed, 17 insertions, 12 deletions
diff --git a/sound/soc/fsl/imx-pcm-fiq.c b/sound/soc/fsl/imx-pcm-fiq.c
index 34043c55f2a..2fc872b2def 100644
--- a/sound/soc/fsl/imx-pcm-fiq.c
+++ b/sound/soc/fsl/imx-pcm-fiq.c
@@ -44,7 +44,8 @@ struct imx_pcm_runtime_data {
struct hrtimer hrt;
int poll_time_ns;
struct snd_pcm_substream *substream;
- atomic_t running;
+ atomic_t playing;
+ atomic_t capturing;
};
static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)
@@ -56,7 +57,7 @@ static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)
struct pt_regs regs;
unsigned long delta;
- if (!atomic_read(&iprtd->running))
+ if (!atomic_read(&iprtd->playing) && !atomic_read(&iprtd->capturing))
return HRTIMER_NORESTART;
get_fiq_regs(&regs);
@@ -124,7 +125,6 @@ static int snd_imx_pcm_prepare(struct snd_pcm_substream *substream)
return 0;
}
-static int fiq_enable;
static int imx_pcm_fiq;
static int snd_imx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
@@ -136,23 +136,27 @@ static int snd_imx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
case SNDRV_PCM_TRIGGER_START:
case SNDRV_PCM_TRIGGER_RESUME:
case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
- atomic_set(&iprtd->running, 1);
+ if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+ atomic_set(&iprtd->playing, 1);
+ else
+ atomic_set(&iprtd->capturing, 1);
hrtimer_start(&iprtd->hrt, ns_to_ktime(iprtd->poll_time_ns),
HRTIMER_MODE_REL);
- if (++fiq_enable == 1)
- enable_fiq(imx_pcm_fiq);
-
+ enable_fiq(imx_pcm_fiq);
break;
case SNDRV_PCM_TRIGGER_STOP:
case SNDRV_PCM_TRIGGER_SUSPEND:
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
- atomic_set(&iprtd->running, 0);
-
- if (--fiq_enable == 0)
+ if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+ atomic_set(&iprtd->playing, 0);
+ else
+ atomic_set(&iprtd->capturing, 0);
+ if (!atomic_read(&iprtd->playing) &&
+ !atomic_read(&iprtd->capturing))
disable_fiq(imx_pcm_fiq);
-
break;
+
default:
return -EINVAL;
}
@@ -200,7 +204,8 @@ static int snd_imx_open(struct snd_pcm_substream *substream)
iprtd->substream = substream;
- atomic_set(&iprtd->running, 0);
+ atomic_set(&iprtd->playing, 0);
+ atomic_set(&iprtd->capturing, 0);
hrtimer_init(&iprtd->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
iprtd->hrt.function = snd_hrtimer_callback;