Hi,

I'm currently developing an ALSA ioplug plugin which should transfer audio samples over UART to a DSP (I already wrote that in a previous post).

The DSP wants to receive 156 - 164 audio samples with a sampling rate of 8 kHz and a format of S16_LE each 20 msec (which is more or less the number of audio samples multiplied by the period length of the sampling rate).

My idea is to add a high precision delay to the transfer callback of the ALSA plugin.

Unfortunately, I found out that the hrtimer resolution on the system is as low as 10ms:

------------------------------------------------------------------- kernel: hrtimer resolution: 0 sec, 10000000 nsec, loops_per_jiffy: 448512 -------------------------------------------------------------------

* Does this mean that if I use nanosleep for example each delay has to be an integral multiple of the hrtimer precision and for example a delay of 15ms would not be supported (since it is no integral multiple of 10ms) ?

* It is possible to increase the precision (e.g. by changing the kernel configuration) ?

* Do you know a better solution for the task, where the task is to send and receive audio samples to/from the DSP over UART and the timing is critical ?

cheers, Stefan