Idling direwolf makes a farting sound

szatox · Advocate Joined: 27 Aug 2013 Posts: 3200

I figured it's time to dust off direwolf again and try to actually set some things up this time, and the next thing I knew was this chirping/farting sound from my speakers which starts just after sending the first frame and then simply won't go away until I kill direwolf.

I happened to do a kernel upgrade in the meantime, so it's occurs on at least 2 recent kernel versions, both direwolf 1.6 and 1.5 (of course I downgraded to test the most obvious suspect), and also I get the same result using ax25 interface connected to KISS pseudoterminal and some random application I used to send a beacon over AGW (network) connection.
Even dropped the config file to make sure it's not a mistake on my part.

I had JACK clone DW's output to audacity; although I did not measure the frequencies, the waveform looks like a bunch of 1s followed by a single 0 (at 1200b) followed by silence, looping forever multiple times per second. Like it tried to keep the line busy or something...
However, to make it even more confusing, debug does not report activating PTT at that time, so apparently DW does not intend to put this noise on air.
Also, it stops briefly when it has some data to send: there's a short gap, the data frame, and then the same farting noise returns.

Meanwhile, direwolf 1.6 on borrowed ubuntu works as expected with the defaults (AKA no config file): sends ARP request as ordered and then shuts up waiting for more work. I even managed to receive via laptop's builtin mic on gentoo, after taking care not to send anything via freshly started DW, so it's not completely broken either.
I wonder what could I have possibly screwed up, and every single time for that matter. One'd think a 5 minute search should come up with a solution, but so far looks like it's a problem exclusive to yours truly.
Welp. Any ideas?

Edit: it kinda sounds like a stuck ring buffer, though my sound works perfectly fine otherwise. I mean, there are system sounds, media players and so on, and none of those gets stuck. And most apps I use are not actually jack-aware, they all talk via alsa-bridge, just like direwolf.

eccerr0r · Posted: Thu Jul 20, 2023 5:49 pm Post subject:

I've only tried using direwolf with Pulseaudio and did not hear it passing gas.

Did the kernel report (in dmesg) any buffer issues? What about jack (probably in syslog)?

I haven't used direwolf in a while, and sorry not a jack user... btw, curious, used wsjtx with jack, does that work?
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szatox · Advocate Joined: 27 Aug 2013 Posts: 3200

There's absolutely nothing in logs.
Well, I'm going to enable realtime scheduling like recommended for jack once emerge completes building some stuff. It shouldn't really matter, but it shouldn't be making weird noises either, so Im trying... things.

Can't get wsjtx to open sound devices it just throws a vague error saying it can't open the audio device. Which also is weird, my default audio device does talk to multiple applications at the same time.
I also realized I don't have sound on root, for reasons currently unknown. Not that I care, since I've been running direwolf as a my own user anyway. But it made me somewhat curious, so I'll check it out too. Maybe.
I'm thinking about running direwolf under gdb... Already tried strace and it showed me - you guessed it - nothing.

eccerr0r · Posted: Fri Jul 21, 2023 2:22 am Post subject:

I'd think it's a jack problem or at least an interface between direwolf and the alsa-jack converter...
Back in the day when pulseaudio was in its infancy I do recall strange sound problems when using it with legacy alsa apps and its converter.

Incidentally I need to install a second sound card into my computer, accidentally transmitted an auto-play audio from a webpage into the FT8 frequencies...oops... at least it was low power.
_________________
Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
What am I supposed watching?

szatox · Advocate Joined: 27 Aug 2013 Posts: 3200

Huh... Yeah, you might be on to something.
After disabling jack the problem does go away. I wonder if I can make direwolf stay on alsa while the other applications go via jack. Looking at alsa's configs it should be doable, though I'll definitely need to study them first.
Thanks

eccerr0r · Posted: Fri Jul 21, 2023 9:49 pm Post subject:

correct, I'm using vox right now as it seemed easiest as I really didn't want to waste a serial port yet - at least not until I can get a serial port for programming into my hf rig...
_________________
Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
What am I supposed watching?