ECE497 Lab11 Using the Open Sound System (OSS)

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Be sure you have done Lab 10 before this lab so all your software is set up.

Lab 11/6 - Using the OSS Driver

Lab 11 is Lab 6 is on pages 171-186 of DaVinci-OMAP_Workshop_v2.0.pdf. In doing this lab you will get audio from the line-in jack on the Beagle and sent it out the speaker jack.

  • Go to the class dfs site and get:
    • setpaths.mak
    • setpaths.sh
  • Move the setpaths files in the workshop directory to another location.
host $ cd workshop
host $ mv setpaths.sh setpaths.sh.orig
host $ mv setpaths.mak setpaths.mak.orig
  • Copy the setpaths files you got from DFS into the workshop directory. In Lab 11/6 you will edit these files so they are correct.

You will still need the symbolic link from part 5, and make sure to update the file paths.

Problems and Solutions

I find that running

cat /dev/dsp > /dev/dsp

gave me this error:

-sh: can't create /dev/dsp: Device or resource busy

This did not seem to cause problems until part b of the lab. I found this website to solve my problem. Apparently, the problem is that pulseaudio is using /dev/dsp, and refuses to give it up. When I killed pulseaudio (the rude way, not the graceful way), then running cat /dev/dsp > /dev/dsp worked, and my executable worked. I don't know what killing pulseaudio does to the system, I haven't noticed any ill-effects yet...