option OSS requires SDL_AUDIO

Trying to compile SDL20 I got the following message. It took a while before I realized that this wasn't a library that I needed to install, I needed to reconfigure SDL20 to add the SDL_AUDIO option.
To do that I simply ran "make config" in the SDL20 port directory and added SDL_AUDIO.

FreeBSD: X needs Python 3.5 at least, but 2.7 was specified.

When trying to compile using the ports system, the error message that something needs Python 3.x, but 2.7 was specified is quite common.
This is due to the ports system "remembering" the python version that was specified by a top level package, while a dependency may require something else.

The solution is to manually compile the dependency first.

In my case I was trying to build sdl_sound, but it failed due to meson-0.51.2 needs Python 3.5 at least, but 2.7 was specified.
To fix this I compile meson first, then I go back and compile sdl_sound.

Set CPU Frequency on Raspberry Pi in FreeBSD

While benchmarking I noticed very low results with FreeBSD. Apparently the Raspberry Pi 2 is locked to the low frequency of 600MHz, while in Ubuntu a governor scales it between 600 and 900.
My first try was to edit /boot/msdos/CONFIG.TXT but the different overclocking values applicable for Linux did not affect FreeBSD.

The solution was to enable powerd in FreeBSD.

Add the following to /etc/rc.conf
powerd_enable="YES"
powerd_flags="-a hadp"

That will enable powerd to utilize frequency scaling from 600MHz to 900MHz depending on load. hadp means hiadaptive mode and is a scaling leaning towards more performance.
You can read more via "man powerd" and also try out different modes live, by running for example:
powerd -v -a hadp

Sources:
vzaigrin
nobugware

Portsnap fetch fails in RaspBSD 12 on RPi3

First I couldn't run 'portsnap fetch' due to the system time being off.
Snapshot appears to have been created more than one day into the future!
(Is the system clock correct?)
Cowardly refusing to proceed any further.

Setting the time using the command 'ntpdate' fixed that issue, but got me a new instead:
Verifying snapshot integrity... Segmentation fault (core dumped)
snapshot corrupt.

This can be worked around by manually installing the ports tree.
wget http://ftp.freebsd.org/pub/FreeBSD/ports/ports/ports.tar.gz
tar xvf ports.tar.gz -C /usr/

Sources:
FreeBSD documentation - using ports
slug

Resizing the root partition in RaspBSD 12

I was trying to resize the root partition for RaspBSD 12 on a Raspberry Pi 3 and ran in some trouble, since growfs showed "operation not permitted".

Here was my solution to resizing:
gpart show
This showed that my disk was named mmcsd0 and that my root partition had the index "2".

gpart resize -i 2 -a 4k -s 20gb mmcsd0
Here I'm resizing the root partition, 2, to 20gb

gpart commit
save the changes

service growfs onestart
resize the file system

Sources:
FreeBSD.org documentation
DigitalOcean