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support for period wakeup disabling

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Add API to disable period wakeups.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@intel.com>
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
This commit is contained in:
Clemens Ladisch 2010-11-15 10:43:13 +01:00
parent 70dded6aba
commit 7c99bd24bc
4 changed files with 79 additions and 1 deletions
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72
src/pcm/pcm.c
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@ -726,8 +726,11 @@ int snd_pcm_nonblock(snd_pcm_t *pcm, int nonblock)
return err;
if (nonblock)
pcm->mode |= SND_PCM_NONBLOCK;
else
else {
if (pcm->hw_flags & SND_PCM_HW_PARAMS_NO_PERIOD_WAKEUP)
return -EINVAL;
pcm->mode &= ~SND_PCM_NONBLOCK;
}
return 0;
}
@ -3080,6 +3083,23 @@ int snd_pcm_hw_params_can_sync_start(const snd_pcm_hw_params_t *params)
return !!(params->info & SNDRV_PCM_INFO_SYNC_START);
}
/**
* \brief Check if hardware can disable period wakeups
* \param params Configuration space
* \return Boolean value
* \retval 0 Hardware cannot disable period wakeups
* \retval 1 Hardware can disable period wakeups
*/
int snd_pcm_hw_params_can_disable_period_wakeup(const snd_pcm_hw_params_t *params)
{
assert(params);
if (CHECK_SANITY(params->info == ~0U)) {
SNDMSG("invalid PCM info field");
return 0; /* FIXME: should be a negative error? */
}
return !!(params->info & SNDRV_PCM_INFO_NO_PERIOD_WAKEUP);
}
/**
* \brief Get rate exact info from a configuration space
* \param params Configuration space
@ -4199,6 +4219,56 @@ int snd_pcm_hw_params_get_export_buffer(snd_pcm_t *pcm, snd_pcm_hw_params_t *par
return 0;
}
/**
* \brief Restrict a configuration space to settings without period wakeups
* \param pcm PCM handle
* \param params Configuration space
* \param val 0 = disable, 1 = enable (default) period wakeup
* \return Zero on success, otherwise a negative error code.
*
* This function must be called only on devices where non-blocking mode is
* enabled.
*
* To check whether the hardware does support disabling period wakeups, call
* #snd_pcm_hw_params_can_disable_period_wakeup(). If the hardware does not
* support this mode, standard period wakeups will be generated.
*
* Even with disabled period wakeups, the period size/time/count parameters
* are valid; it is suggested to use #snd_pcm_hw_params_set_period_size_last().
*
* When period wakeups are disabled, the application must not use any functions
* that could block on this device. The use of poll should be limited to error
* cases. The application needs to use an external event or a timer to
* check the state of the ring buffer and refill it apropriately.
*/
int snd_pcm_hw_params_set_period_wakeup(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val)
{
assert(pcm && params);
if (!val) {
if (!(pcm->mode & SND_PCM_NONBLOCK))
return -EINVAL;
params->flags |= SND_PCM_HW_PARAMS_NO_PERIOD_WAKEUP;
} else
params->flags &= ~SND_PCM_HW_PARAMS_NO_PERIOD_WAKEUP;
return snd_pcm_hw_refine(pcm, params);
}
/**
* \brief Extract period wakeup flag from a configuration space
* \param pcm PCM handle
* \param params Configuration space
* \param val 0 = disabled, 1 = enabled period wakeups
* \return Zero on success, otherwise a negative error code.
*/
int snd_pcm_hw_params_get_period_wakeup(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
{
assert(pcm && params && val);
*val = params->flags & SND_PCM_HW_PARAMS_NO_PERIOD_WAKEUP ? 0 : 1;
return 0;
}
/**
* \brief Extract period time from a configuration space
* \param params Configuration space