Date: 2023-12-21
Last Updated: 2024-03-01

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. ^†

†. https://docs.ipi.wiki/com-hpc/ava/How_to_install_Nvidia_Graphic_Card_Driver.html (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

See also:

Discussion on the ampere computing forum about AMD GPU bugs and patches.

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.

...

ECAM access

Ampere Altra supports only 32-bit ECAM reads. Linux includes a quirk fix.

https://github.com/torvalds/linux/commit/877c1a5f79c6984bbe3f2924234c08e2f4f1acd5

discussion on LKML

Tips for mainline kernel

When you want to use the mainline kernel with defconfig, also enable the following config options.

• DRM_AMDGPU

• FW_LOADER_COMPRESS, FW_LOADER_COMPRESS_ZSTD

CMDLINE flags

pcie_aspm=off amdgpu.aspm=0 amdgpu.runpm=0 ^†

†.https://community.amperecomputing.com/t/amd-gpus-on-the-altra-devkit-and-other-altras-patches-available-now/336

Other AVA platform information pages

• AVA, Xen & kernel: hardware notes, debugging tips & tricks