Re: [alsa-devel] [PATCH 2/2] add API to allow disabling period interrupt

Sorry for not answering sooner.

Pierre-Louis Bossart wrote:

(No filtering in pcm_multi and pcm_direct info fields)

I'm not sure whether filtering or not filtering would be a good idea for yet unknown flags.

• • It is not allowed to call this function when given configuration is not exactly one.

... +int snd_pcm_hw_params_can_disable_period_irq(const snd_pcm_hw_params_t *params)

This function is useless because it cannot be called before snd_pcm_hw_params_set_period_irq().

• • This function should be called only on devices where
• • #snd_pcm_hw_params_can_disable_period_irq() returns true. (too late, FIXME)

Therefore, this paragraph needs to go away.

I think there should be a flag that can be added to snd_pcm_open, like SND_PCM_NO_AUTO_RESAMPLE.

• • Even with disabled period interrupts, the period size/time/count parameters
• • are valid; it is suggested to use #snd_pcm_hw_params_set_period_size_last().
• • When period interrupts are disabled, the application must not use poll() or
• • any functions that could block on this device.

We should also mention that the application must call some update function often enough.

Regards, Clemens