[alsa-devel] Fwd: Overrun Errors - SAM9G

[Akshay Mishra]

On 22 July 2014 11:32, Bo Shen <voice.shen at atmel.com> wrote:

> 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>)
>
>
do you mean, disabling HRTimer you had -EPIPE ? I am positive on disabling
the HRTimer, CPU Freeze which made the -EPIPE vanish and the moment I
enable it, I again get -EPIPE. :-(


> Actually, I can not understand why you add a usleep(1) in this piece of
> code. :(
>
>

Bo, as I mentioned earlier -- the usleep is only a placeholder. Any system
call (like write to serial port) also gives same result but since I cannot
ask you to do serial transmit - you may not have it setup I asked you to do
a usleep since it gives me the same result.

I have requested for a SAM9G45-EK from the local Atmel office and once I
get it I shall inform you further on this on the same platform.

-Akshay



>
>  The code is from here (http://www.linuxjournal.com/node/6735/print).
>>
>>
>>         Please advice,
>>         Akshay
>>
>>
> Best Regards,
> Bo Shen
>
>