Pi-series sound output options

[Karl Denninger]

Ugh.

This morning I had a repeat of a problem I've run into before and it
hosed me good -- a production Pi2 unit failed to restart after a power
failure.  It hung after the "UE0" ident line.

This is related to the fact that I have to run updated bootcode
(bootcode.bin and related files) on that device because the stock
bootcode that FreeBSD-11 uses along with u-boot is severely-unstable for
sound output.  Specifically, after some period of time it will simply
stop talking on the sound port and nothing fixes it other than a reset.

With the updated bootcode and setting pwm_mode=2 sound is stable - IF it
boots.  The problem is that it doesn't /always /boot; the failures are
lockups during some part of the device probe process, and are fatal.  If
you power cycle a few times it will eventually come up and once it does
it's fine.

Attempting to use even /later /versions of the bootcode and related
files (like, for instance, the current stuff now out there) results in
mmc not being seen and thus you can't mount root, so trying to roll
forward isn't an option either as those are completely non-functional. 
There appears to be a clash between the DTB file and the updated
firmware in some fashion.  Pulling over the newer DTB from the Linux
side of the world associated with the newer bootcode results in a
non-booting FreeBSD kernel.

I'd go to the Pi3 (despite no integrated WiFi) in places where I need
this capability except that on the Pi3 we have no sound *at all* at
present in the code because the vchiq driver doesn't exist and won't
compile "as-exists" today.

This application NEEDS sound output capability.  I don't care if it's on
a plug-in via USB but it has to work in a "FreeBSD-like" manner (e.g.
open up a PCM channel, etc.)

Are there any options with this platform available at present or am I
stuck with porting this app to Linux (yuck; among other things the
"NanoBSD" option on FreeBSD is nice for reliability reasons!)

-- 
Karl Denninger
karl at denninger.net <mailto:karl at denninger.net>
/The Market Ticker/
/[S/MIME encrypted email preferred]/
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