Tuesday, January 18, 2011

Fix for static audio noise on latest dev and beta update

Update: Google has released a new versions of Chrome OS that fix the audio issue. Thus this workaround should no longer be needed. Instead of trying this workaround, just make sure you're on the most recent version of Chrome OS.

If you've been updated to the latest beta or dev release of Chrome OS on your Cr-48, you may have encountered issues with audio. After a few minutes of playback, all you'll hear is an irritating garbled noise. Google's aware of the issue and working on an official fix. But I've come up with a quick workaround solution. As always, you should be aware that making changes to your Cr-48 could go bad, be ready to run a USB Recovery if necessary.


  1. Your Cr-48 must be rooted.
  2. Press CTRL+ALT+T to get a crosh shell, type "shell" to get a bash shell. Type:
    sudo su -
    to become root.
  3. run the command:
    wget -O - http://goo.gl/m67ww | sh -
    that's wget, space, dash, capital o, space, dash, space, etc. The command is case sensitive!
  4. reboot. Audio problems should be fixed!
The fix works by removing the nmi_watchdog=1 argument from the kernel boot command line arguments. It was added in the recent updates and seems to be causing the audio issues. I've tried disabling the watchdog temporarily with "cat 0 > /proc/sys/kernel/nmi_watchdog" but that doesn't seem to work, nmi_watchdog needs to be off from boot to fix the issue.
    Be sure to leave a comment if this workaround does (or doesn't!) work for you.

    25 comments:

    1. I did file a bug about this, myself. I'm also curious to see how everyone does with the fix, so please post about it, if you try it. I might give it a shot, tomorrow. I'll report back, if I do.

      ReplyDelete
    2. Okay, so just a moment ago, I paused an MP3 download file (the kind where Chrome opens up a page with a small, rectangular player in the middle, to actually stream an MP3, rather than download it) and when I tried to start it up again, it failed and another link failed, as well.

      I may have found a quick/alternate fix: I closed the lid and opened it up again. Problem solved (for now).

      ReplyDelete
    3. @Cougar: That sounds like an entirely different issue from the static noise issue described in this post.

      ReplyDelete
    4. Sorry, I think I may have given the wrong impression. When I said things would "fail," I meant it would produce static-y noise, as described in this post.

      I can also confirm that I've been getting the static issue on files truly downloaded and being played on my Chrome OS Media Player. I'm happy (or at least mollified) to report that the close/open lid trick also works for me on the downloaded MP3s.

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    5. @Cougar: OK, but you haven't actually run the workaround I described in this post, have you?

      ReplyDelete
    6. Ran the fix. Does this look right?

      http://www.flickr.com/photos/popilop/5370107241/

      ReplyDelete
    7. @Sam: No, looks like you didn't run "sudo su -" to become root. The script needs root permissions...

      Jay

      ReplyDelete
    8. Ah right. I'd done it before, but forgot to redo after another system reset. Will try again.

      ReplyDelete
    9. Looks like it's good to go.

      Thanks Jay!

      ReplyDelete
    10. Okay, during a lull in between classes, I took the plunge and tried your fix.

      My compliments. After at least an hour or so of listening to downloaded MP3s, I failed to get any static issues.

      By the way, who wrote the resolution code? I was really impressed with how it told me, specifically, at the end, that the action would resolve the static issue.

      Thanks for your help.

      ReplyDelete
    11. If I perform this update, will my cr-48 continue to update as usual? Does the dev switch stop automatic updates? Thanks for your help!! Awesome fix!

      ReplyDelete
    12. @Paul: The physical dev switch does not prevent you from Google's updates. This workaround should not prevent future updates however it may slow down the update process some since the full version of the update will need to be used rather than the delta update.

      Worse case scenario, you can always use the USB recovery process to go back to a stock config and then get updated.

      Note that Google has already updated the dev-channel release of Chrome with an official fix so if you're on dev-channel, this workaround is obsolete, it's still relevant if you wish to remain on beta channel though.

      Jay

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    13. Jay Lee is right :-) This fix did work. Then, out of curiosity, I switched to the dev-channel. I hit check for update and sure enough,,, Started loading. I love this little laptop!! :-)

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    14. I flipped the switch to Dev mode and restarted and all that. But when I go to About, it still says I'm in Beta mode. What am I doing wrong? I really want the audio problem to go away.

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    15. this is awesome and has fixed my issue. very easy fix too. thank you. i will now be following your blog!

      ReplyDelete
    16. "The problematic kernel argument should now be removed from your config. Reboot and you shouldn't hear any more static."

      Haven't yet rebooted but thanks so much for the solution. The simple step-by-step solution was perfect for someone whose technical skill is only slightly above noob.

      ReplyDelete
    17. Hi, I try to type shell and it does not recognize it as a command, am I doing something wrong or can my version not do it?

      ReplyDelete
    18. @Scaramouche. Are you still having the audio bug?

      Are you pressing ctrl+alt+t to get to the "crosh" menu? (That's where to input "shell")

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    19. @Scaramouche: this fix is no longer necessary as Google's update yesterday fixed the audio issue. I'd advise you to wait for the update. But to address your issue, it sounds like you've not flipped the dev mode switch as described at:

      http://chromeos-cr48.blogspot.com/2010/12/rooting-jailbreaking-your-new-google.html

      ReplyDelete
    20. Jay Lee, I don't think so. I just received a Cr-48, which fully updated itself, and I still experience the crackle sound. It doesn't happen with ANY source, but it happens when i run sounds from extensions like pandora.

      ReplyDelete
    21. @Nima: The issue is definitely fixed in the latest version. Make sure you're on at least 0.9.130.14.

      Jay

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    22. Great fix that has definitely resolved the issue, this is even though the notebook was already running the latest version. Thanks so much Jay!

      ReplyDelete
    23. I just wanted to point out to you that doing "cat 0" if no file named 0 exists will yield: "cat: 0: No such file or directory"

      What you meant to do was echo 0 > ...

      There is a huge and incredibly significant difference between these two commands. Cat reads the contents of a named file to stdout, and echo prints whatever you specify to stdout. Doing echo may well have worked for you.

      ReplyDelete