diff options
| author | Oskar Schirmer <oskar@scara.com> | 2013-11-12 15:46:38 +0000 |
|---|---|---|
| committer | Mark Brown <broonie@linaro.org> | 2013-11-14 12:59:44 +0000 |
| commit | fc7dc61d9a87011aaf8a6eb3144ebf9552adf5d2 (patch) | |
| tree | 4d6e4007b7fd6bd144fadd4ef01390728304876d | |
| parent | 71d0c3a876e007f68fc2ed433119dd4f4dc408a7 (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
| -rw-r--r-- | sound/soc/fsl/imx-pcm-fiq.c | 29 |
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 34043c55f2a6..2fc872b2deff 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(®s); @@ -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; |