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