PostmarketOS on the Oneplus 6
-----------------------------

Somehow i always find ways to make life a bit more ... ehm
... "challenging", so after the battery on my Oneplus One
running Ubuntu Touch starts now to severly degrade and only
lasts for about 2 - 3 hours i had the opportunity to grab a
discarded Oneplus 6. 

Of course i could not simply run it with its stock android
system or even Ubuntu Touch... nah, it has to be something
more special. In this case: PostmarketOS, a real, complete
Linux system running on a phone, this was a thought i simply
could not escape ;-)

## Preparation and installation

There are some options for the user interface avaiable, the
most user friendly i guess would be Phosh or Plasma
mobile... but hey, we are not here for the userfriendlyness,
are we? We are here for engineerfriendlyness! So the obvious
choice was to go with SXMO (a tiling window manager).

Following the (really good) guide in the PostmarketOS wiki i
prepared the installation, unlocked the bootloader with
fastboot and flashed the appropiate images. Against my
inital fears everything went completely smooth and about 30
minutes after the start i was greeted by a couple of
penguins, followed shortly after by the SXMO desktop.

So, what now? I connected the phone via the system menu to
my wifi, added the nececcary APN info for mobile data and
began to install the tools i normally have in my desktop
Linux installations. 

Now the little problems began:

I was only able to get extremly quiet, garbled sound playing
back from the build in speakers or a bit less quiet but as
much garbled sound from the headphone jack whatever i tried
with alsa. So what to do? I had lying around a pair of
bluetooth headphones... why not try those?

## Bluetooth

First i enabled the bluetooth service ("service bluetooth
start"), after that i could find and pair the device via the
system menu. So, but still no audio playback... after a bit
of reading i found out that i had to install BlueALSA, i did
so and started the regarding service ("service bluealsa
start") now i tried playing back a wav file i grabbed from
the net and... voila, i get audio output! Ok, now i set up
the deamons to start at boot-time ("rc-update add bluetooth"
"rc-update add bluealsa"). But a problem remains: The
settings are not system wide... a thing i have to
investigate further...

At least i could get youtube playback working by adding the
bluetooth device as the default output for mpv by adding the
following to my mpv.conf:
 
> volume=20 audio-device=alsa/bluealsa

Now i was able to get good audio quality with the supplied
user scripts for youtube playback.


## Further problems

While mobile data works flawlessly i for now could not get
audio calls to work. I did knew beforhand that this is a
known issue with the Oneplus 6 but after i have read on
Github that there was recent progress on this issue [1] i
have hope that this will be a solved problem soon. If not...
now then there is still the option of getting a SIP client
to work and use that.

=> https://gitlab.com/postmarketOS/pmaports/-/issues/1338
[1] Issue 1338 [enchilada] missing audio in calls

## Conclusion so far

Now i have a quiet powerfull Linux workstation in my pocket
(the installed tools will be described in a future post when
i can say if they work out for me) and a new project to
tinker with. So far i am quiet happy and will at least try
to get everything to work.