Ilya Ivanov

DevOps eXtraordinaire

Greetings, fellow netizen. Today we’re going to install Ubuntu on Redmibook 16 Ryzen edition (Ryzen 4700U).

Ubuntu version

First off, choosing Ubuntu version. There’s 20.04 LTS and 20.10 at this point. But the only important difference between them is kernel version, which is 5.4 in 20.04 and 5.8 in 20.10. The new kernel can be installed on LTS too, though, so we’re going to pick 20.04.

Installation

Installation works properly. No issue here, just follow the standard procedure. The only strange thing is that it won’t connect to 5Ghz wifi. 2.4 Ghz works.

Display brightness

Right after first login, trying the brightness buttons, it turns out that they don’t work. A quick search turns up this. Apparently, this needs kernel 5.5, and some sources even say 5.7.

Well, no problem. Installing a newer kernel:

sudo apt install linux-generic-hwe-20.04-edge

This gets us to 5.8 (at this point).

Reboot and see that brightness buttons now work!

Bluetooth

And right after that, another hiccup. A bluetooth mouse won’t get detected by the laptop. However, a headset works fine. Trying to do a lescan yields no result. Time to search again. Bugzilla has some info with apparently the same problem. Specifically, it mentions Realtek RTL8822CE device.

Let’s see if we have that one:

lsusb
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 002: ID 0cb5:c547 Realtek Bluetooth Radio
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Looks like it’s one of the devices mentioned in bugzilla: 0cb5:c547, meaning RTL8822CE. And here’s a patch for it. Of course, it’s not in the kernel yet, so we’ll have to do some compilation.

Instead of compiling the whole kernel, as suggested in the discussion, let’s try to compile btusb module only. Should be faster and less work. We’ll still need to the sources for the whole kernel, of course.

sudo apt install git build-essential kernel-package fakeroot libncurses5-dev libssl-dev ccache bison flex # some packages for building
wget https://github.com/torvalds/linux/archive/v5.8.tar.gz # since we're on 5.8 kernel
tar zxf v5.4.tar.gz
cd linux-5.4/drivers/bluetooth
vi btusb.c

Apply the patch, save it.

Then, as described here (you should still be in linux-5.4/drivers/bluetooth):

make -C /lib/modules/$(uname -r)/build M=$PWD modules

Now, custom btusb.ko is in the same directory. Let’s try to load it:

cp /usr/lib/modules/$(uname -r)/kernel/drivers/bluetooth/btusb.ko ~/btusb.ko.bak
cp btusb.ko /usr/lib/modules/$(uname -r)/kernel/drivers/bluetooth/btusb.ko
modprobe -r btusb
modprobe btusb
...could not insert btusb.ko: Operation not permitted

Oops. What’s wrong? Dmesg to rescue:

Lockdown: modprobe: Loading of unsigned module is restricted; see man kernel_lockdown.7

Riiight, so the module is not signed, and the kernel refuses to load it. Unfortunately, the only way to do that is to disable UEFI Secure Boot. So:

  1. Reboot.
  2. Enter BIOS (F2)
  3. Set a supervisor password if there isn’t one yet.
  4. Disable Secure Boot.
  5. Save and exit.

Check dmesg again:

dmesg | grep -i blue
[    1.987803] usb 1-4: Product: Bluetooth Radio
[    9.839189] Bluetooth: Core ver 2.22
[    9.839205] Bluetooth: HCI device and connection manager initialized
[    9.839208] Bluetooth: HCI socket layer initialized
[    9.839210] Bluetooth: L2CAP socket layer initialized
[    9.839212] Bluetooth: SCO socket layer initialized
[    9.858744] Bluetooth: hci0: RTL: examining hci_ver=0a hci_rev=000c lmp_ver=0a lmp_subver=8822
[    9.860923] Bluetooth: hci0: RTL: rom_version status=0 version=3
[    9.860925] Bluetooth: hci0: RTL: loading rtl_bt/rtl8822cu_fw.bin
[    9.864089] Bluetooth: hci0: RTL: loading rtl_bt/rtl8822cu_config.bin
...

Great, it loads rtl8822 driver, which is what we need.

Try to pair with the mouse again (don’t forget to put it into pairing mode!). It works even without hcitool lescan. Yay!

And just so we don’t get any funny bussiness with accidental kernel upgrade, let’s pin kernel version:

sudo apt-mark hold linux-generic-hwe-20.04-edge
apt-mark showhold
  linux-generic-hwe-20.04-edge

WiFi

  1. Still can’t connect to 5 Ghz WiFi.
  2. The mouse feels choppy. No amount of tinkering with Bluetooth settings helps. It could be due to interference of Bluetooth with 2.4 Ghz wifi.

So let’s get on that. Without going into long details, let me say that the only thing that actually works is an alternative driver from this repo. However, the version from PatoJad apt repo failed to install on kernel 5.8 (the fix is on github, but it appears that the debs weren’t rebuilt with it yet). So, installing from deb directly:

wget https://github.com/juanro49/rtl88x2ce-dkms/releases/download/5.7.3_35403_1/rtl88x2ce-dkms_35403_amd64.deb
sudo dpkg -i ./rtl88x2ce-dkms_35403_amd64.deb
sudo modprobe rtl88x2ce

… No change. Apparently, we need to unload old modules.

$ sudo apt install hwinfo
$ hwinfo --wlan
10: PCI 100.0: 0282 WLAN controller
  [Created at pci.386]
  Unique ID: yWPJ.iGV+_7vRbHF
  Parent ID: e6j0.JhR1dXh1J9E
  SysFS ID: /devices/pci0000:00/0000:00:01.2/0000:01:00.0
  SysFS BusID: 0000:01:00.0
  Hardware Class: network
  Model: "Realtek WLAN controller"
  Vendor: pci 0x10ec "Realtek Semiconductor Co., Ltd."
  Device: pci 0xc822 
  SubVendor: pci 0x1d2e 
  SubDevice: pci 0xc823 
  Driver: "rtw_8822ce"
  Driver Modules: "rtw88_8822ce"
...

Right, rtw_8822ce is still used for the device. Checking /etc/modprobe.d, looks like blackisting is also not applied by the deb package. Let’s do that manually:

wget https://raw.githubusercontent.com/juanro49/rtl88x2ce-dkms/master/rtw88_blacklist.conf
sudo cp rtw88_blacklist.conf /etc/modprobe.d/rtw88_blacklist.conf

And now, reboot. (You can do some modprobe commands to enable it without reboot, but anyway it’s better to check that everything works from scratch).

hwinfo --wlan
10: PCI 100.0: 0282 WLAN controller                             
  [Created at pci.386]
  Unique ID: yWPJ.iGV+_7vRbHF
  Parent ID: e6j0.JhR1dXh1J9E
  SysFS ID: /devices/pci0000:00/0000:00:01.2/0000:01:00.0
  SysFS BusID: 0000:01:00.0
  Hardware Class: network
  Model: "Realtek WLAN controller"
  Vendor: pci 0x10ec "Realtek Semiconductor Co., Ltd."
  Device: pci 0xc822 
  SubVendor: pci 0x1d2e 
  SubDevice: pci 0xc823 
  Driver: "rtl88x2ce"
  Driver Modules: "rtl88x2ce"
...

Now we’re talking! Connect to 5Ghz - works! And mouse movement is no longer choppy, too!

Although, now for some reason there’s 2 WLAN devices reported in hwinfo output. And the Gnome shows 2 wifi devices as well. Well, nevermind as long as it works.

Night light

Night light worked strangely. For some reason it would get enabled and the right away go back to daylight setting. Then I installed Redshift, which worked fine. Then I disabled Redshift and tried Night light again. This time, there was no problem. Magic?

Anyway, if NL doesn’t work for you, just use RS instead:

sudo apt install redshift redshift-gtk

Fn button

If F1-F12 work as if Fn is always pressed, use Fn+ESC combination to switch the default mode.

Still doesn’t work

Suspend/hibernation. It’s a known issue that will supposedly get resolved in kernel 5.10. Of course, then we’ll likely have to jump through the hoops with Bluetooth again, and possibly WiFi too.

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