Pinebook Pro: Build Notes

This page details things that are different/notable about the way in which elementary OS has been tweaked to run on the Pinebook Pro.

Kernel

Thanks to the great work that the Manjaro ARM team have done in this field, getting a working kernel for the Pinebook Pro was relatively painless. We've simply taken a mainline kernel straight from kernel.org, applied a few patches copied from the Manjaro repository and used a config set similar to the Manjaro one. It needed tweaking slightly to be compatible with the way Ubuntu/elementary works.

For example, we've had to disable kernel module compression in the kernel config as this isn't compatible with the Ubuntu update-initramfs scripts yet.

Unfortunately, Ubuntu hasn't released any kernels that are new enough or contain the necessary tweaks, options and patches to run on the Pinebook Pro yet. So this is one major area where the Pinebook Pro builds differ from the regular Intel/AMD builds. You'll notice that we're using kernel 5.7.11 currently, though this is likely to be upgraded to 5.8 soon (as it allows dropping some more patches that have been mainlined).

elementary normally relies heavily on the fantastic work done by Canonical in testing and maintaining kernel releases. So maintaining our own kernel configuration and patchset is a bit of a departure from that. Ubuntu already releases specific kernels for the Raspberry Pi, perhaps we'll see a ready made Pinebook Pro one in the future. In the short term however, we may consider packaging the Pinebook Pro kernel into a .deb and hosting it on a PPA, so we can push updates in future if necessary. Currently the kernel is just built into the image at build time.

Performance

Unfortunately, despite elementary being a relatively light distribution, performance still isn't as good as you would hope given the capability of the hardware. This is down to GTK3 largely not using GPU acceleration, especially when running on Xorg. There are a number of tweaks we've applied to improve the experience somewhat, though there won't be any big leaps in performance until we can move the stack to Wayland and to a greater extent GTK4.

The first tweak we applied was disabling the ondemand CPU governor which is forced on by default as a systemd unit on Ubuntu. This allows the kernel to use the schedutil governor which has been enabled and set as the default in our kernel config. The schedutil governor is a much newer governor with an awareness of the different performance/power utilisation levels of the big.LITTLE cores in the ARM CPU. Switching to this gave an immediate noticeable gain in performance.

Both ondemand and schedutil scale the frequency of the processor cores in response to load. However, if they aren't doing this efficiently or if the CPU has delays or slowdowns while it's switching frequency, you notice a bit of latency while the frequency picks up, then things feel a bit more speedy for a few seconds and then they slow down again.

We've opted to increase the minimum frequencies of both the CPU and GPU to reduce some of this sluggishness. This has the downside of reducing the battery life slightly. But given the already excellent battery life, we felt it was a reasonable trade-off.

If you wish to disable these frequency tweaks and have longer battery life but worse performance instead, you can comment out the lines in /etc/tmpfiles.d/cpufreq.conf and reboot.