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/dev/dsp open failure

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Posted by Appalayagari Sreedhar

on Oct 03 2011 09:17 AM

Intellectual885 points

Hi,

I have developed a audio driver, the audio ic is interfaced with the TI DM365 processor MCBSP ports.

I am working with the 2.6.32 kernel.

I am able to play the audio using the aplay command. but when i try to open the device using /dev/dsp i am getting the -ve value. it fails to open the device.

when i check the

>> ls /dev/dsp

it is available in the device directory.

I have enabled the Sound OSS related options in the kernel menuconfig. with the same options i am able to open the device for the tlv320aic3x device on DM365 leopard evm.

Could anyone please suggest where i am doing wrong? and help to solve this problem.

Thank you, Sreedhar.

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Posted by Appalayagari Sreedhar

on Oct 04 2011 09:59 AM

Intellectual885 points

Hi,

When i tried to open the /dev/dsp in Read only mode it is success.

could you please tell me how i can open the /dev/dsp in read write mode.

Thank you, Sreedhar

Posted by Appalayagari Sreedhar

on Oct 12 2011 04:15 AM

Intellectual885 points

Hi,

Any clue about this issue.

TIA , Sreedhar

Posted by Vaibhav Bedia

on Oct 12 2011 09:06 AM

Expert5115 points

Hi,

You mentioned that you are able to use the dsp node with the aic codec. Can you describe what changes you have done after which it is not working.

Regards,

Vaibhav

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Posted by Appalayagari Sreedhar

on Oct 13 2011 01:20 AM

Intellectual885 points

Hi,

The menuconfig options are same for the aic3x codec and for the codec which i have developed,

when i try to open the open the device using the /dev/dsp it is success for aic3x but failure for my audio codec in READWRITE mode.

the failure happens in READWRITE mode. it is success in READONLY mode.

i feel i am missing something in my audio driver which is causing the problem when i try to open the device using the /dev/dsp.

but after i do aplay and try to open the device using the /dev/dsp in READWRITE mode it works.

I could not figure it out where is the problem. please provide your suggestions.

Thank you, Sreedhar

Posted by Vaibhav Bedia

on Oct 17 2011 05:56 AM

Expert5115 points

Hi,

There might be some flag in the driver setup that you are missing. Can you compare the flags in the aic3x and your custom driver?

Regards,

Vaibhav

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Posted by Appalayagari Sreedhar

on Oct 17 2011 07:34 AM

Intellectual885 points

Hi vaibhav,

Thank you very much. i will do the same.
on further probing and testing.

i found that if i open the device separately O_WRONLY and O_RDONLY mode it works.
if i try to open the device using the O_RDWR mode it fails.

is there any configuration settings i need to check.

-Sreedhar

Posted by Appalayagari Sreedhar

on Dec 06 2011 04:21 AM

Verified Answer

Verified by Appalayagari Sreedhar

Intellectual885 points

Hi Vaibhav,

I found the problem. in my audio driver.

In snd_soc_dai structure i have commented the

//.symmetric_rates = 1
then this issue not coming.

I verified this structure in tlv320aic3x.c file there is no such
parameter, so i commented this and resolved this problem.

-Sreedhar