Re: [alsa-devel] Fwd: Overrun Errors - SAM9G

22 Jul 2014

      Hi Akshay,
On 07/22/2014 10:38 AM, Akshay Mishra wrote:
...
On 22 July 2014 07:57, Bo Shen <voice.shen@atmel.com
mailto:voice.shen@atmel.com> wrote:
Hi Akshay,

On 07/17/2014 08:54 PM, Akshay Mishra wrote:

    Hello,
          I am trying a simple alsa capture on the Atmel ARM9
    (SAM9G45). While
    only capture runs fine, putting any os call on the same thread
    gives XRUNs.

    Even a innocent usleep(1) seems to lead to regular XRUNs.
    Eventually I want
    to dump this capture on the serial port and I am not able to get
    past this.

Do you test with alsa utils. If yes, where you add the usleep(1) in
code?

    I have tried on AT91 linux as well as on kernel 3.10.10-rt7 with
    no success.

I try both kernel and don't reproduce this issue with alsa utils.

Bo, I put usleep(x) after the snd_pcm_readi. I also tried with this code
(attached).
usleep at Line 88 gives the error.
Another observation is, disabling HRTimer the -EPIPE error was not seen
but I need further tests to be sure about this behaviour.
In contrast, I enable HRTimer, the -EPIPE error is gone.
I briefly go through the code: usleep --> .. --> nanosleep (define in 
<kernel/hrtime.c>)
Actually, I can not understand why you add a usleep(1) in this piece of 
code. :(
...
The code is from here (http://www.linuxjournal.com/node/6735/print).
    Please advice,
    Akshay

Best Regards,
Bo Shen