PineNote Development/Building Kernel

Building the Kernel

After followed Dorian's directions to get Arch installed you've seen someone playing DOOM and you want to learn how to get the features that enable that kind of performance. To get your PN running this smoothly, we'll need to build our own kernel. There are two kernel efforts underway right now:

1. pgwipeout: https://gitlab.com/pgwipeout/linux-next
2. smaeul: https://github.com/smaeul/linux/tree/rk35/pinenote-next

We'll be using smaeul's kernel + some additional patches provided by DorianRudolph, pgwipeout, Maximilian Weigand, occam_razor, and hrdl. Thanks so much to them, and all the other users who have worked on piecing together drivers, twiddling configs, answering questions, and sharing their work in other ways. Brava!

Perhaps the main component of the kernel is the DRM driver. You can read more about the driver by reading Smaeul's RFC.

A small warning

This guide is completely based off of the scripts provided by Maximilian. We'll be cloning and running them, but he owns them and he -- or others -- might change them. It's smart to have a look at what's going on, check when this page was last updated vs when his scripts were last updated, etc. Be nimble!

Additionally, as Maximilian warns here, these changes are all experimental and may damage your panel.

Note: If anyone reading this has recommended reading for how we can understand what may damage our panels (IE is the risk in fast updates? The types of updates? something more complicated?), please add it here!

What you should have already done

I assume you've already got an operating system installed on your Pinenote other than the stock Android. Doing this isn't trivial, but it is well understood -- you will be following the footsteps of many others. Dorian Rudolph made a guide for doing this, available here.

What do you need to know?

If you followed Dorian's guide to get here and felt semi-comfortable, you'll be fine. This is no more complicated than that. If you are intimidated, that's okay! I'll still encourage you to try :) you will learn a lot, just be patient and don't put any data on your PineNote that you wouldn't be okay losing. If you run into trouble, ask for help in the Discord/Matrix. Please try to solve problems on your own first, and then ask for help -- if nobody replies, please be patient and ask again soon.

Steps to build

1. Clone Maximilian's scripts:

 $ git clone https://github.com/m-weigand/mw_pinenote_misc.git 

2. Make a separate directory for patching the kernel. Then run Maximilian's clone_and_prepare_git.sh. This will clone smaeul's kernel and a number of patches. Read the script to see which patches it is using. Feel free to open the patches too -- it's helpful to get a slim idea of what's going on, if only looking at the commit messages in them:

 $ cd ../
 $ sh mw_pinenote_misc/custom_kernel/clone_and_prepare_git.sh

3. Compile the kernel:

 $ sh ./mw_pinenote_misc/custom_kernel/compile.sh 

4. Next we want to perform the work captured in install_to_pn.sh, but the work may vary slightly from person to person. For example, I believe Maximilian is running Debian Sid, and I am running Manjaro -- because of this, and personal preference, some of our files live at different places. As long as you put them somewhere and configure your extlinux.conf to point at it, things will be okay. Looking at install_to_pn.sh, we can see that there are three pieces to installing the kernel: the kernel image (called Image), the device tree (rk3566-pinenote-v1.2.dtb), and the modules. All of these files have been compiled and placed into the linux/pack folder. The easiest way to send these over is by using scp or rsync -- read the script and decide how you would like to get your files in the correct location. You may need to install rsync on your PineNote if it doesn't already have it.
   1. If it helps, I installed my dtb like this: $ scp rk3566-pinenote-v1.2.dtb root@pinenote:/boot/dtbs/rockchip/
   2. After installing the dtb as above, I updated my /boot/extlinux/extlinux.conf to point to this new file (previously, my dtb did not have the -v1.2 on the end).
   3. (Perhaps not necessary?) The last step is to generate a new initrd image. (If you're like me and don't know what initrd is, the wiki is very enlightening.) This is done on the PineNote itself. Send Maximilian's installation script over and run it. Then place the generated image (from the last step of the shell script) into your boot partition and update extlinux.conf if needed to point at this new file.

       $ scp initrd/gen_uboot_image.sh root@pinenote:/root # Do this part on local to put script on PN
       $ ssh root@pinenote # Or use UART, the dongle + picocom, and change to root
       $ cd /root
       $ ./gen_uboot_image.sh
       $ mv initrd.img /boot/initrd.img
       $ vim /boot/extlinux/extlinux.conf # Update this to reference this new initrd image
      

   4. At this point your kernel is in place! However, there are a few more steps you may need to complete to ensure the display and networking continue to work:
      1. For display, you may need to change /lib/firmware/waveform.bin to /lib/firmware/rockchip/ebc.wbf (TODO is this a difference between PG and smaeul's kernel? or a patch?)
      2. For networking (and I imagine more as well), you may need to change /lib/firmware/pinenote.bin to /lib/firmware/pinenote-v1.2.bin
   5. This part technically isn't kernel specific, but we need to install a patched version of Mesa. If you are running an Arch based system, you're in luck! occam_razor provides prebuilt patched packages (say that 5 times fast) here. Simply extract these files, send them to PN, and install them using the package manager. You can also patch it yourself by looking at Maximilian's compile_mesa.sh.
      Note: If you frequently update your system with something `pacman -Syu`, you will end up updating these packages and losing the patches. Add this line to your /etc/pacman.conf to prevent them from being updated:

      IgnorePkg = libva-mesa-driver mesa mesa-debug mesa-vdpau opencl-mesa vulkan-mesa-layers vulkan-broadcom vulkan-panfrost vulkan-radeon vulkan-swrast

   6. To ensure the GPU stays on, we need to use Maximilian's mweigand_eglinfo.service. The Readme.md in that same directory has instructions for how to install this, but basically we need to copy it to /etc/systemd/system/, run sudo systemctl daemon-reload to make sure systemd knows it exists, then execute sudo systemctl enable mweigand_eglinfo.service
   .

   That should be it! Now are equipped with the freshest kernel + patches.

   Next Steps

   Configuring the driver

   The driver has several options that can improve performance. These can be read about here. Personally, I use rockchip_ebc.bw_mode=1 rockchip_ebc.default_waveform=1 rockchip_ebc.refresh_threshold=30 rockchip_ebc.auto_refresh=1 to make the image lower quality, but much faster to update. The auto_refresh setting is also essential to clear ghosting which will otherwise accrue on screen. I added the above settings the APPEND line in my extlinux.conf to make sure they are applied on boot.

   Fixing Suspend

   If you're using a logind system, edit your /etc/systemd/logind.conf config. More information on what to do in Arch's documentation.

   Configuring your apps

   See this page.

   Booting Linux instead of Android

   PineNote Development/Booting Linux

   Fixing Bluetooth

   Some users have noticed instability with their wireless driver. Upgrading the driver to the version provided by LibreELEC may help! To do this, download the BCM4345C0.hcd, brcmfmac43455-sdio.bin, and brcmfmac43455-sdio.txt from the libreELEC repositories and place them in the same location as your previous firmware (`/lib/firmware/brmc/`). Then rename brcmfmac43455-sdio.{txt,bin} as `brcmfmac43455-sdio.pine64,pinenote-v1.2.{txt,bin}`. If this doesn't help, ask about it in the matrix chat!

   Autoconnect to your Bluetooth devices

   This bluetooth-autoconnect project may help.

   Preliminary fix for stuttering bluetooth audio

   Following a fix used for the Quartz Model A (which uses the same SoC as the Pinenote), we can modify the device tree prior to building the kernel to try to mitigate poor bluetooth audio streaming. (reference: see https://lore.kernel.org/linux-arm-kernel/20220926055435.31284-1-leo@nabam.net/T/)

   Steps:

   • Open arch/arm64/boot/dts/rockchip/rk3566-pinenote.dtsi
   • Go to line 939, "bluetooth", under the "uart1" section
   • Edit the two lines that read "device-wake-gpios" and "host-wake-gpios"; you want them to read "device-wakeup-gpios" and "host-wakeup-gpios" respectively
   • Add the following line to the end of the bluetooth section (under the vddio-supply line in my .dtsi): "max-speed = <3000000>;"
   • Count your zeros, don't forget your punctuation..

   Caveats:

   This will improve BT audio quality at least when using the AAC codec. In my experience, the quality is more than acceptable, but there are still issues apparent: occasional isolated stutters even on AAC; prohibitively frequent stutters on SBC-XQ remain. Fully resolving BT audio issues might require further changes similar to the one described above, or may alternatively be a matter of audio software settings (e.g., process priority, audio server buffer settings). Investigation ongoing..