Hi,

The second issue is resolved too. I was using /dev/dsp to access the Default sound card -> card0. (1) The /dev/dsp is mapped (through a symbolic link) to /dev/sound/dsp by default, when the system boots up. So, all works fine for me. (2) When I connect a usb-audio-device to my system, (a) the /dev/dsp1 gets mapped to /sound/dev/dsp1 (b) And /dev/dsp too gets mapped to /sound/dev/dsp1 So, I could not access /sound/dev/dsp. Is it not a bug? (3) When I dis-connect the usb-audio-device from my system both the "/dev/dsp" and "/dev/dsp1" entries dis-appear from my system. Is this not a bug too?

Every thing will work fine for me as long as I use entries /dev/sound/dspN, insteading of /dev/dspN. I think this issue must be fixed. Shall I report a bug or something? In any case, I will spend some time in fixing this issue, when I get free from current assignment.

Thanks and Regards, Kunal

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Hi All,

The first issue was resolved by disabling the "CONFIG_SND_PCM_OSS_PLUGINS http://lxr.linux.no/linux/+code=CONFIG_SND_PCM_OSS_PLUGINS".i.e. disable the OSS plug-in support under KernelConfigMenu->sound->alsa

CAN SOME ONE PLEASE HELP ON THIS? (2) Once I connect the iPod to my target, I can not any more use the default sound card. I read on the oss-emulation tutorial that this could be a problem with "dsp_map". But I am not able to check the current settings.

Thanks and Regards, Kunal

Date: Mon, 26 May 2008 20:10:11 +0530 From: Kunal Singh <kunal at singhkunal.com> Subject: [alsa-devel] problem with usb-audio and oss emulation To: alsa-devel at alsa-project.org Message-ID: <483ACBCB.2020800 at singhkunal.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Hi,

I am working on a ARM based target with 2.6.23 Kernel. My project involves streaming data from a USB-Audio Device (an iPod) and playing it back on the target. I am using OSS-emulation API to communicate with the audio devices. What I am able to do: (1) I have a sound card in my target. This is mapped to card0. I can open the "dsp" device and can playback any audio data on this. (2) I have enabled the usb-audio module support in kernel configuration. When I connect iPod to the target, I can see a new card "card1" being added in the /proc/asound/ directory. (3) I can open the "dsp1" device and can read from it. When I connect a "USB-Analyzer" I can see some valid data being streamed to the target.

However, I am stuck with following issues: (1) The data being received on the target (in user mode) is junk. I put some printfs in the function "retire_capture_urb" in file "/linux/sound/usb/usbaudio.c", and I can see that the "data" which I see through usb-analzyer is reaching till this point. However, there seem to be some problem with one of the "snd_pmc_oss_ReadN" functions in file "http://lxr.linux.no/linux/sound/core/oss/pcm_oss.c". I am not able to exactly trace the problem, but I think that the "byte count" and "buffer address" being passed to snd-usb-audio is getting messed up some where. Has any one faced similar problems before? (2) Once I connect the iPod to my target, I can not any more use the default sound card. I read on the oss-emulation tutorial that this could be a problem with "dsp_map". But I am not able to check the current settings.

Can some one give me some pointers for further debugging?

Thanks and Regards, Kunal Singh www.singhkunal.com

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