Re: [alsa-devel] ALSA utility aplay/arecord error

[Takashi Iwai <tiwai@suse.de>]

At Mon, 10 Mar 2008 11:59:04 +0800,
Saurav SAHU wrote:
> 
> Hi all
> 
> The platform on which I am trying to perform ALSA playback and record with USB sound device is based on a MIPS CPU running Linux kernel 2.6.14. The kernel uses non-coherent DMA in the configuration:
>   CONFIG_DMA_NONCOHERENT=y
>   CONFIG_DMA_NEED_PCI_MAP_STATE=y
>   CONFIG_CPU_BIG_ENDIAN=y
>   CONFIG_SYS_SUPPORTS_BIG_ENDIAN=y
>   CONFIG_BOOT_ELF32=y
>   CONFIG_MIPS_L1_CACHE_SHIFT=5
> I have attached the kernel .config file for further information. So far, I have not succeeded in hearing sound with 'aplay', or capturing sound with 'arecord'.
> 
> If there have been any similar issues reported on ALSA usage with MIPS CPU based on non-coherent DMA in the past, please let me know. Also, if there have been any patches developed for successful resolution of this issue on similar platform/configuration, it would be very useful for me.

Yes, there is a known long-standing problem wrt cache coherency.
Try to disable the mmap support in the driver as a test.


Takashi

> 
> Thanks & Regards
> Saurav
> 
>   ----- Original Message ----- 
>   From: Saurav Sahu 
>   To: alsa-user@lists.sourceforge.net 
>   Sent: Friday, March 07, 2008 4:33 PM
>   Subject: Re: ALSA utility aplay/arecord error
> 
> 
>   I have been able to resolve the previously reported errors by setting the environment variable for ALSA configuration file on the target filesystem of the embedded platform.
> 
>   However, I do not hear any audio from USB sound device with speaker-test or aplay:
> 
>   Upon using arecord for recording, I get an error:
> 
>   Is this problem related to a low-level driver issue which may not be working well on target platform? Could there be a DMA related issue as the samples don't seem to be transferred to the USB audio device.
> 
> 
>     ----- Original Message ----- 
>     From: Saurav Sahu 
>     To: alsa-user@lists.sourceforge.net 
>     Sent: Thursday, March 06, 2008 4:28 PM
>     Subject: ALSA utility aplay/arecord error
> 
> 
>     Hello
> 
>     I am working towards using ALSA for playback and capture on an embedded platform running Linux. The kernel uses ALSA driver version 1.0.10rc1. I had manually built and installed ALSA library (v1.0.10) and ALSA utilities (v1.0.10) for the target platform filesystem. I have a USB audio device (C-Media) connected to the USB port of the board and it seems to be successfully successfully detected by the driver.
> 
>     However, when I run ALSA utilities like aplay, arecord or speaker-test, I observe errors opening the hardware device which may be related to the configuration on the filesystem.
> 
>     Are these errors from ALSA utility/library due to the detection of hardware, ALSA configuration files or something else related to my target device filesystem?
> 
>     Thanks in advance for any help. Do let me know if you need any more details.
> 
>     Best Regards
>     Saurav

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