GRAPHICS

PHYSICAL OUTPUT

The AVA contains an Aspeed VGA output, and some display managers (gdm3 confirmed) choose it by default, even if it’s not connect and even though HDMI is available. I could not find any config setting or work around to make gdm3 ignore the VGA output except for disabling the ast kernel module:

root@ava:~# cat > /etc/modprobe.d/ast.conf <<'EOF'
blacklist ast
EOF
root@ava:~# reboot

gdm3 + wayland

If gdm3 refuses to launch with wayland, it might be because of udev rules forcing xorg (e.g. see if file /lib/udev/rules.d/61-gdm.rules) exists. The override conf is written to /var/run/gdm3/custom.conf which you can edit and then restart gdm3.

Graphics during booting process with GPUs

There is no UEFI GOP driver support on AVA, according to ADLINK. ^†

†. ADLINK Industrial Pi Wiki (Retrieved 2024-02-26) (Archive.org snapshot)

However, you can enable graphics during boot by flashing the GPU’s ROM. Instructions on how to flash arm64 EFI OptionRom on an AMDGPU

PCI

MMIO access

The PCI standard implementation in the AVA platform has a few problems. PCI devices that require unaligned MMIO reads, like a GPU, require a patched kernel to overcome those problems.

Some patches come from Ampere themselves, and a single patch reverts an amdgpu change that makes it not work on AVA.

Note: Build the patched kernel with CONFIG_ALTRA_ERRATUM_82288=y

You can find a 6.5.11 kernel with rebased patches here: https://github.com/epilys/linux/tree/6.5.11-ampere-pci-fixes and 6.6.2 here https://github.com/epilys/linux/tree/6.6.2-ampere-pci-fixes

The original (not rebased) patches are also attached as files in this page. The amdgpu patch has been merged into linux but might be missing from earlier versions and need to be applied.