Arch Linux is sometimes labelled as unstable, but in reality it's the bleeding edge options that can make it unstable. I've opted for stability, so I'm using the LTS kernel.
Install the LTS kernel
sudo pacman -S linux-lts
sudo grub-mkconfig -o /boot/grub/grub.cfg
sudo reboot
Remove the state-of-the-art kernel
sudo pacman -R linux
sudo grub-mkconfig -o /boot/grub/grub.cfg
sudo reboot
I had to remove acpi_call and tp-smapi before removing the tip kernel, and reinstall them using the DKMS versions in the AUR.
Why and How to install the LTS kernel in Arch Linux