Re: Can not access UDRC after updating software

Annaliese McDermond

On May 29, 2018, at 10:10 AM, Herb Weiner <herbw@...> wrote:


Thank you, thank you, thank you. Adding that missing line to config.txt and rebooting resolved the problem, and I can now see the UDRC with aplay -l and access the UDRC with alsamixer.

So now, the only remaining questions are:

  • Is there any known explanation for why my /boot/config.txt was missing the dtoverlay= line, or should I just accept that computers do funny stuff like this all the time?
Because it wasn’t necessary in the past.  To fix some other problems, we upgraded the alder kernel to 4.9.x rather than the previous 4.4.x line.  This was partially to keep up with what Raspbian is doing and make things work well together.  Unfortunately, the Device Tree Overaly, which tells the kernel what hardware is out there and where it lives on a hat like the udrc, was incorrect for the new kernel revision.  I made a new overlay, but the Pi has to be told to include it.  That’s what the config.txt changes are designed to do.  At some point we hope to have a field upgrader for the flash chip on the UDRC that should fix the error.  We need to make it pretty reliable and foolproof, though, otherwise we just cause more issues.
  • Should I be concerned that /etc/apt.d/sources.list.d/compass.list does not exist?
No.  I’m not in front of my Pi right now as I’m at $day_job, so I was going from memory on where we put the compass repository definition.
  • How can I determine whether I'm on the "alder" release?
It’s going to be in either /etc/apt/sources.list or in a file contained in /etc/apt/sources.list.d.  It’ll be a line that refers to

Compass releases are named after trees in alphabetical order.  Alder was our first release, Birch was a failed release that was never ready for prime time, and we hope to come out with “cedar” soon.  The next will probably be “dogwood” but that’s a ways off.

Wilderness is our “experimental” builds.  That version is built on the very latest code nightly and packaged together into the images.  It’s a completely automated process and it isn’t tested in any way, so that version blows up occasionally when I need to do something to it.  People are more than welcome to use it with the understanding that I may blow up your whole Pi with a change I make at any point in time and I generally don’t react well to crying regarding that breakage.  The tree releases are considered to be stable and we try not to break those at all, and we certainly want to know if we do.


— Anna

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