Am 23.08.2025 um 09:59 schrieb Julien Grall:
Out of interest, sorry if this was already mentioned before, is there any reason ACPI is used on the Raspberry PI over Device-Tree? Is there any issue with the latter on Xen?
Perhaps I can chime in here and point out why I have been using ACPI on Raspberry Pi (RPi) with Xen. This is my personal experience as a user, and I don't really know much about Device Trees, so I can't make a technical analysis of ACPI vs. DT.
Debian is currently the only linux distribution I am using. Therefore, I am used to setting up Xen by installing Debian and then installing the packages from Debian. When installing these packages, I end up with a ready-to-use Xen/Dom0 setup and Grub as the bootloader. When I install kernel updates, grub automatically is updated to use the correct Xen/kernel combination as a default. This is very convenient.
My first tries with a RPi were with RPi OS. However, RPi OS doesn't provide Xen packages. Next, the official explanations on [1] seemed rather complicated to me. Coming from Debian, I didn't know anything about U-Boot. As I didn't want to mess with U-boot, I installed vanilla Debian (following [2]), which provided me with the familiar ACPI/Grub/Debian environment. With Julien's help, I managed to compile Xen (with ACPI switched on) on the RPi, got it running, and have been using it since then with an occasional recompile of Xen. (There are still some networking related issues I experience in certain setups, but that's a different story.)
So, to sum it up, the combination of ACPI/Grub/Debian and a self-compiled Xen package provided a solution that comes close to the experience I have on my other Xen systems. Apart from some deviation when installing vanilla Debian and the need to compile Xen myself (due to the experimental status of ACPI, of course), I can basically use and manage the RPi system like any x86 system. That's why I am using it this way.
From my point of view, the biggest drawback of the ACPI solution is that I can't use I2C because I2C is not supported when using UEFI boot on a RPi. [3]
Nowadays, there are semi-official packages for RPi provided by Debian, but as they use a different boot mechanism, they break my workflow, that's why I haven't been using them.
Best regards, Paul [1] https://xenproject.org/blog/xen-on-raspberry-pi-4-adventures/ [2] https://forums.raspberrypi.com/viewtopic.php?t=282839 [3] https://github.com/pftf/RPi4/issues/130
