[General Questions and Answers] PokeRekoP:
Hi all,

with the web overflowing ~30 years after it's invention I can't g**gle this...

UPDATE 1: restored the S4 to a stock Android 5.0.1. Settings > My Device > Accessories > enable

"Audio Output Mode"

=> Plays music through the dock's jack allright => Conclude: must be somehting with Lineage. Will try a more recent AOSP-10 based rom later...

/UPDATE1.

UPDATE2: tried with an AOSP 10 based HavocOS version. Doesn't work, Options are the same as in the LOS based ROM. => is there no non-stock rom out there supporting the damn samsung docks!?

/UPDATE2

UPDATE3: now raised this question in the Samsung S4 Q+A forum; please excuse the double-posting; mods may close this here (but please don't delete as I didn't take the full details over)

https://xdaforums.com/t/audio-through-mulitmedia-dock-3-5mm-jack.4313687/

/UPDATE3.

-- original post below --

tl;dr: how to get 3.5mm audio jacks on Samsung docking stations to work?

I have two devices, Samsung Tab 2 and Galaxy S4 (yes, old, but for what I'd like to do still what you want for "no money").

For each I have an original Samsung Docking Station ("Desktop Dock EDD-D1E2BE" and "Multimedia Dock EDD-S20EWE", respectively), each with a 3.5mm audio jack at the back.

EDIT:

- The Tab2's station is "stupid", i.e. it only splits out the (30pin?) connector into the data / power lines (keeping the same plug / connector geometry) and the audio leads. No chips inside that dock.

- The S4's dock contains a usb hub (3 Ports), HDMI connector, and the audio jack and micro-USB port. Several chips inside. Not sure if there's anything like a USB-connected audio chip ("DAC"?) in there, would have to get the glued PCB out to get some understanding (maybe). So here LOS might need some sort of "driver" to talk to the audio DAC and then the jack?

/EDIT.

The Tab 2 runs a dated Lineage 14.1 (Android 7.1.2), and the S4 (ks01ltexx) a more recent LOS 18.1 / Android 11.

Want to use media apps (radio streaming ...) to send audio output through that jack to our living room amp. Yes, I could plug the 3.5mm audio cable into the device's own jack, but that's ugly as hell. Plus, want to be able to take the device (which wouldn't matter in the end, happy to get one combo to work) out of the dock, select the stream etc, and once it plays (then through the crappy device's speakers) set the device back into the cradle and have it re-route through the rear jack - without plugging a cable.

Doesn't work in either, and I can't find any related options in the settings / get it to work.

On the LOS 14.1, there's Settings > Sounds > Other Sounds > Dock-Speaker (?) (translating from my system language here, might not be fully correct) where there's two options "All Audio Sources" and "Only Audio Sources from Media" (wording doesn't really make sense, also not in my native language). Neither does change anything.

Also on the LOS 14.1, in the Developer Options, there is the selection for the "USB Configuration" offering "charging", "MTP", "PTP", "RNDIS", "Audio Source", and "MIDI". None of them does the trick, and "MIDI" can be selected but is never realy "set", i.e. it reverts back to what was set before when entering this option screen again.

In the LOS 18.1, "Audio Source" and "MIDI" aren't there, I have "file transfer" (I think that's MTP in earlier versions), "USB tethering", "PTP", "no data transfer" (which would be "charge only" I think).

On both, another developer option is "disable USB audio routing", which is switched off (so it should allow to route USB audio to the dock I would expect).

All these options in various combinations make no difference on either device. Also, I'd think that making it work should be possible even without any dev options.

Is there's a general issue with docking stations, audio and LOS? Have been through various versions over the years with the Tab 2 and occasionally re-tested the dock/jack thing - never worked, but never really looked into it. Only thing not tried is to go back to a stock samsung FW (which would be an Android 5.0 or so for the galaxy S4, possibly even worse for the Tab2).

Q: is it generally possible to enable the sound via the docks? Anyone using similar combinations with any LOS or other ROM?

Cheers.