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ALSA: pcm: add snd_pcm_hw_rule_noresample()

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Add a helper function to allow drivers to disable hardware resampling
when the application has specified the SNDRV_PCM_HW_PARAMS_NORESAMPLE
flag.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Clemens Ladisch 2011-09-16 23:03:02 +02:00 committed by Takashi Iwai
parent 84f9df159d
commit d5b702a64b
2 changed files with 28 additions and 0 deletions
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2
include/sound/pcm.h
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@ -825,6 +825,8 @@ int snd_pcm_hw_constraint_step(struct snd_pcm_runtime *runtime,
int snd_pcm_hw_constraint_pow2(struct snd_pcm_runtime *runtime,
unsigned int cond,
snd_pcm_hw_param_t var);
int snd_pcm_hw_rule_noresample(struct snd_pcm_runtime *runtime,
unsigned int base_rate);
int snd_pcm_hw_rule_add(struct snd_pcm_runtime *runtime,
unsigned int cond,
int var,

26
sound/core/pcm_lib.c
View file

@ -1399,6 +1399,32 @@ int snd_pcm_hw_constraint_pow2(struct snd_pcm_runtime *runtime,
EXPORT_SYMBOL(snd_pcm_hw_constraint_pow2);
static int snd_pcm_hw_rule_noresample_func(struct snd_pcm_hw_params *params,
struct snd_pcm_hw_rule *rule)
{
unsigned int base_rate = (unsigned int)(uintptr_t)rule->private;
struct snd_interval *rate;
rate = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
return snd_interval_list(rate, 1, &base_rate, 0);
}
/**
* snd_pcm_hw_rule_noresample - add a rule to allow disabling hw resampling
* @runtime: PCM runtime instance
* @base_rate: the rate at which the hardware does not resample
*/
int snd_pcm_hw_rule_noresample(struct snd_pcm_runtime *runtime,
unsigned int base_rate)
{
return snd_pcm_hw_rule_add(runtime, SNDRV_PCM_HW_PARAMS_NORESAMPLE,
SNDRV_PCM_HW_PARAM_RATE,
snd_pcm_hw_rule_noresample_func,
(void *)(uintptr_t)base_rate,
SNDRV_PCM_HW_PARAM_RATE, -1);
}
EXPORT_SYMBOL(snd_pcm_hw_rule_noresample);
static void _snd_pcm_hw_param_any(struct snd_pcm_hw_params *params,
snd_pcm_hw_param_t var)
{