Latest kernel patch for PiTFT causing usb audio problems

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asdfrewq
 
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Latest kernel patch for PiTFT causing usb audio problems

Post by asdfrewq »

Hi guys! I'm having some problems using the latest kernel patch for the pitft in conjunction with a usb dac. I have found that using the latest patch, required for b+ compatibility, introduces loud distortion on usb audio output. This doesn't affect output from the onboard jack or hdmi. Although it is present regardless which model rpi is used, eg B+ or 256mb B rev 1. These issues are not present on the 0227 beta patch from the faq, but of course, they won't work with the B+ (my preferred platform)

Any idea what's happening here or how I can solve this?

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adafruit2
 
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Re: Latest kernel patch for PiTFT causing usb audio problems

Post by adafruit2 »

Wow, never heard of that one! :) No idea at this time, we'll see if we can figure it out but we aren't really sure where to start. Note that the kernel itself doesn't require a patch for model B+ support, its the stuff in /boot (firmware and load thingies)

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tacoma
 
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Re: Latest kernel patch for PiTFT causing usb audio problems

Post by tacoma »

I installed the PiTFT software today and just started encountering this same problem. I can confirm if happens only after installing the PiTFT software. If I revert my SD card to the image I backed up prior to the installation it's fine. I was able to repeat this several times. I tried on several B Models (rev 1 and rev 2).

As the OP stated the onboard audio is fine but the USB Audio (purchased from Adafruit) experiences loud crackling sounds. I was hoping to use the PiTFT and USB Audio together but I will have to find an alternative solution.

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gilles504
 
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Re: Latest kernel patch for PiTFT causing usb audio problems

Post by gilles504 »

Hello,
I had the same issue and same configuration (easy install image for a PiTFT capacitive + audio adapter from adafruit).
I fixed the issue with forcing usb mode to 1.1

http://wiki.linuxaudio.org/wiki/raspber ... usb11_mode

seems good now :)

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adafruit_support_mike
 
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Re: Latest kernel patch for PiTFT causing usb audio problems

Post by adafruit_support_mike »

Interesting.. we'll put that in our list of things to watch out for.

Thanks for posting the solution!

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tacoma
 
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Re: Latest kernel patch for PiTFT causing usb audio problems

Post by tacoma »

gilles504 wrote:Hello,
I had the same issue and same configuration (easy install image for a PiTFT capacitive + audio adapter from adafruit).
I fixed the issue with forcing usb mode to 1.1

http://wiki.linuxaudio.org/wiki/raspber ... usb11_mode

seems good now :)
Awesome! I will have to try this out. Thank you so much!

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tacoma
 
Posts: 15
Joined: Fri Nov 30, 2012 9:27 pm

Re: Latest kernel patch for PiTFT causing usb audio problems

Post by tacoma »

gilles504 wrote:Hello,
I had the same issue and same configuration (easy install image for a PiTFT capacitive + audio adapter from adafruit).
I fixed the issue with forcing usb mode to 1.1

http://wiki.linuxaudio.org/wiki/raspber ... usb11_mode

seems good now :)
I can confirm your tip worked perfectly for me. Thank you so much!

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