At Fri, 27 Apr 2007 13:27:00 +0100, Gordon Miller wrote:
Hi
All my snd_pcm_readi calls return too few frames. Also when I switch to stereo, the sound is muted. I cannot change this by adjusting period & buffer sizes. dsnoop is enabled by default. The documentation for snd_pcm_readi says that the only way that the frame count can be short is because of a signal or xrun. Well this clearly isn't the case.
Actually, the documentation is wrong, IMO. The typical behavior of read syscall is that it returns a value actually read by that call. It doesn't guarantee whether the requested size is filled, and can be shorter than requested. As snd_pcm_readi() emulates the read syscall, it should behave in that way.
The blocking mode means that the function waits until the threshold (watermark) condition is fulfilled.
Takashi