[alsa-devel] safe support for rewind in ALSA
kvehmanen at eca.cx
Mon Feb 1 23:10:18 CET 2010
spamming with one more mail.
On Mon, 1 Feb 2010, Kai Vehmanen wrote:
> - at T3, application calls snd_pcm_delay() to query how many samples
> of delay there is currently (e.g. if it write a sample to ALSA
> PCM device now, how long before it hits the speaker)
> - note that this is what snd_pcm_delay() is specifically for
> Anyways, the main problem is that snd_pcm_delay() accuracy is limited by
> the transfer/burst size used to move samples from main memory to the sound
> chip, _although_ the hardware _is_ able to tell the exact current position
It just occured to me that could drivers update 'runtime->delay' in their
pointer callback...? :P And if yes, would it make sense?
Now this would fix snd_pcm_delay() right away (as it already takes
runtime->delay into consideration). Although definitely not sure whether
adding standardized side-effects to pointer() is a good idea...
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