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How to obtain the display with using ACPI data?
Posted: Thu Dec 26, 2024 4:23 am
by TYDQSoft
I was trying to obtain the display framebuffer with using ACPI data or UEFI GOP.
However,I was failed to do this in non-x86_64 architecture qemu virtual machine either using ACPI data or UEFI GOP,especially in riscv64 which don't have both ACPI data and UEFI GOP.
So,How do I obtain the display information and framebuffer with using ACPI data or using UEFI GOP(It is invaild when using non-x86_64 architecture)?
Re: How to obtain the display with using ACPI data?
Posted: Thu Dec 26, 2024 4:51 pm
by Octocontrabass
Does your machine have a display? You can't get information about a display that doesn't exist.
Have you tried Devicetree? Machines that don't support ACPI usually have Devicetree instead.
Re: How to obtain the display with using ACPI data?
Posted: Thu Dec 26, 2024 6:38 pm
by TYDQSoft
Octocontrabass wrote: ↑Thu Dec 26, 2024 4:51 pm
Does your machine have a display? You can't get information about a display that doesn't exist.
Have you tried Devicetree? Machines that don't support ACPI usually have Devicetree instead.
I have display which use spice display protocol and virtIOGPU in non-x64 machines.
QEMU virtual Machine doesn't support ACPI in riscv64 but I don't know how to get the device tree in QEMU virtual machine.
Re: How to obtain the display with using ACPI data?
Posted: Thu Dec 26, 2024 6:56 pm
by Octocontrabass
It depends on how you're booting your kernel.
If you're using UEFI (via OVMF or U-Boot), you'll find the Devicetree using the system table, just like ACPI.
Re: How to obtain the display with using ACPI data?
Posted: Thu Dec 26, 2024 7:31 pm
by zaval
What is your riscv machine firmware? uboot? It doesn't produce GOP for this configuration. No support for diplay or binding it with GOP support or both. Yes, this architecture is so "perspective" only in babblings. In reality, you face an awful "almost nothing supported" mess like what you are trying to deal with. Try looking what it hands to you over system tables. I'm not even sure there is device tree there, which by itself is a yooge hack, capable of only causing pita.
Re: How to obtain the display with using ACPI data?
Posted: Fri Dec 27, 2024 1:32 am
by TYDQSoft
zaval wrote: ↑Thu Dec 26, 2024 7:31 pm
What is your riscv machine firmware? uboot? It doesn't produce GOP for this configuration. No support for diplay or binding it with GOP support or both. Yes, this architecture is so "perspective" only in babblings. In reality, you face an awful "almost nothing supported" mess like what you are trying to deal with. Try looking what it hands to you over system tables. I'm not even sure there is device tree there, which by itself is a yooge hack, capable of only causing pita.
Yeah,my virtual QEMU machine firmware is UEFI.This situation should have been taken into consideration.
Re: How to obtain the display with using ACPI data?
Posted: Fri Dec 27, 2024 12:23 pm
by Octocontrabass
TYDQSoft wrote: ↑Fri Dec 27, 2024 1:32 amYeah,my virtual QEMU machine firmware is UEFI.
Here's the relevant section of the UEFI spec.