At Tue, 20 Jan 2009 21:29:34 +0100, Lennart Poettering wrote:
On Tue, 20.01.09 19:48, Clemens Ladisch (clemens@ladisch.de) wrote:
I currently deal with this by always halving the first wakeup time -- which works most of the time but is a hack.
In theory, you could deduce this behaviour from snd_pcm_hw_params_is_double(), but the USB driver forgets to set this flag.
But still, with this flag I would only now that the startup sequence is "fast". But not how "fast".
I appears to me that it would make a lot more sense if the driver would simply tell me how long I may sleep instead of adding multiple new functions 1) that tell me if double-buffering is used and what the size of the second buffer is, 2) that tell me that data is pulled block-by-block from the buffer and what the block size is, and so on.
The function should look like this:
snd_pcm_sframes_t snd_pcm_busy_for(snd_pcm_t *pcm);I called the prototype "busy for" since effectively the value I am looking for is the time the card will be busy with the data it already has, and doesn't need any new data.
Isn't it snd_pcm_delay() that was originally designed for? Did you check my previous patch?
Takashi