[alsa-devel] Fwd: Overrun Errors - SAM9G

[Bo Shen]

Hi Akshay,

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