I recently purchased a Rock64 SBC (from pine64), which is a fairly powerful and inexpensive micro computer. You can think of it as a more powerful alternative to the famous raspberry pi (to date). The idea is setting this up as a media center for my home and as a micro server, for storing my personal projects in repositories and similar. I also acquired a eMMC module which I haven't tested yet because I have to wait for the serial-USB converter thing to arrive, once I get my hands into this I will let you know in a future blog post.

Installing Linux into SD and first steps

As you could guess, flashing linux into the SD is pretty straightforward, to avoid complications I just used ayufan's images which are already configured to work on the Rock64 SBC. I do have to tell that I had better results using the ubuntu bionic-lxde image for rock64/arm64. I tried with the minimal bionic image but had performance issues that I did not experienced with the lxde one. One of the main reasons for choosing this image is that the experimental hardware acceleration when playing videos allegedly works better with this image.

To flash the SD you just download the desired image in *.img.xz format from the ayufan's repository (link above), insert the SD into your laptop, or whatever device you will be using to flash it, and then use a software to flash it. In my case I found the software Etcher really easy and complete enough to use. You may have Etcher available in your linux package system (I know it's in Solus, which is the Linux distribution I'm using). The process of using Etcher is pretty straightfoward, you just look for the image file, select the SD/SD-reader and click "Flash", it takes some minutes depending on your SD and system. Take into account that Etcher is also available for Windows and Mac.

After it completes, you just plug the microSD into the Rock64 board and turn it on either by plugging it to power or pushing the power button on it. It will load the Linux image from SD automatically. You will then get a login display which you can use rock64 for both user and password and this will end up loading the LXDE desktop environment.

Getting sound to work

After installing and booting Ubuntu image, everything worked as expected except for the sound. As sonn as I logged into the desktop graphical environment I could hear some noises coming from the speakers of the TV that was connected to the Rock64 but no sound, at all, after that. What I thought was that pulseaudio somehow was not working fine in this architecture, therefore I thought of disabling it completely and letting the system use only ALSA, which is built into the kernel. This was the solution indeed and what I did to disable and set up alsa was as follows:

• Disable pulseaudio for the user (it's not recommeded to uninstall it, disabling it should be enough), by following instruction on this site, which was done by running the following instructions:
• cp /etc/pulse/client.conf /home/yourusername/.config/pulse

• Edit the file such that the line with ; autospawn = yes changes to autospawn=no (note there isn't a semicolon at the beggining of the line).

• After disabling pulseaudio the only thing that's missing is configuring ALSA to use HDMI as the audio output. This is done by creating the file /etc/asound.conf with the following content inside it:

pcm.!default {
    type             plug
    slave.pcm       "rock_audio_pot"
}

pcm.rock_audio_pot {
    type            softvol
    slave {
        pcm         "hw:1"
    }
    control {
        name        "Master"
        card        0
    }
}

After this you should just reboot/restart the system.

3D accelerated video playback

As told in ayufan's site, the ubuntu bionic image comes with rkmpv which is a wrapper for mpv to make it use the hardware/GPU acceleration, such that you should only run the following command to play a video in your screen, using the GPU acceleration

rkmpv file.mkv

What I found out is that rkmpv only sets up a specific environment variable and passes some specific parameters to mpv to play the file, I thought on making them the default for my setup, this is achieved by doing the following.

First you have to edit your ~/.bashrc file in your (for example by running nano ~/.bashrc), and append to the end of the file the following line

export LD_LIBRARY_PATH=/usr/lib/aarch64-linux-gnu/gbm:/usr/lib/arm-linux-gnueabihf/gbm

save and close it.

Then you just need to tell mpv to use the expected parameters as default parameters, this is done by creating a file in ~/.config/mpv/mpv.conf with the following content

vo=gpu
gpu-context=drm
hwdec=rkmpp

This will just make mpv use these parameters by default when it's run without manually specified parameters/options.

Conclusion

This basically resulted in what I need so far for the Rock64, which is a basic media center and linux TV, there are some other things I wanted to install to play with it, such as installing tools like peerflix, torrentflix or kodi.

Troubleshooting

I did encounter some other problems, specifically the bionic-minimal image from ayufan didn't work as expected. I tried installing LXQT environment without any luck, all I got was a black screen. Then, I also tried using budgie-wm which did load but the performance was very poor. Still I tried to set up mpv, for video playback, and all the other tools without much luck. This was what finally made me choose to use the Ubuntu bionic-lxde image, which ended up working pretty well.