2010-09-09 11:14:50     audio oddities when reading SD card (spi-mmc)

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2010-09-09 11:14:50     audio oddities when reading SD card (spi-mmc)

Julien Vermillard (FRANCE)

Message: 93303   

 

Hi,

 

On a BF537 stamp with kernel :  2.6.33.2-ADI-2010R1-pre #12 PREEMPT Mon Jul 19 14:54:43 CEST 2010 blackfin unknown

 

I'm currently running a alsa based application (fullduplex 16bit @ 48KHz SSM2603).

 

I'm capturing input and sending back to output for testing purpose.

 

Everything is fine, even if I load the CPU at 100% using "dd if=/dev/urandom of=/dev/null".

 

But when I run "dd if=/dev/mmcblk0p1 of=/dev/null" , xrun occurs, sound stop working and ksoftirqd is consuming a lot of CPU.

 

Even after stoping the command, the sound isn't back. I need to kill and restart my application.

 

There is some tunning (irq?) to do for avoiding mmc-spi to kill the audio system ?

 

Thanks !

 

PS : no kernel message was printed

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2010-09-09 13:52:10     Re: audio oddities when reading SD card (spi-mmc)

Mike Frysinger (UNITED STATES)

Message: 93308   

 

preempt does not work in 2.6.33.x.  you need to be following the latest svn trunk, not some random old vesion.

 

the spi mmc code is known to take over for "long" periods of time because it has to by virtue of the protocol specification.  there might be some tuning in the spi mmc code, but i'm not sure we currently have the resources to work on that.  plus it isnt Blackfin specific, which means it might get even less priority.

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2010-09-09 23:40:02     Re: audio oddities when reading SD card (spi-mmc)

Sonic Zhang (CHINA)

Message: 93317   

 

You may need to tune the SPI MMC framework to do the read/write in a workqueue other than in the softirq.

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2010-09-15 10:48:41     Re: audio oddities when reading SD card (spi-mmc)

Julien Vermillard (FRANCE)

Message: 93467   

 

I upgraded to the last trunk :

 

2.6.34.7-ADI-2010R1-pre #5 PREEMPT Wed Sep 15 16:35:06 CEST 2010 blackfin unknown

 

Same problem, I'll take a look at the spi mmc driver.

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