Hello Philipp,

Thanks so very much for looking into this and it seems like this is an L4Re problem being caught at the inteface of compatibility between leagacy and modern systems. If it can be worked out in some way then I think that this will open the door to L4Re being used on many commodity desktop systems, of which I am currently focusing on the x86_64 based hardware since there is a large contigent of users that have desktop/laptop/tablet system in this area but the ARM systems are also important.

I think that L4Re has great potential to really become a solid competitor to exising platforms although it may take some time to get establised in that arena which is the hopes for my particualr project effort.

I will keep searching an actualy fix for the code and hopefully something will be available soon.

Thanks again and have a great day, Lonnie

On Tuesday, November 26, 2024 12:36 CET, Philipp Eppelt philipp.eppelt@kernkonzept.com wrote:

Hi Lonnie,

I asked around what leads to this behavior and if there is a workaround.

The string is emitted from grub and is usually printed on UEFI systems, because there is no VESA BIOS anymore. There might still be a 'CSM Support' option in your UEFI to enable the legacy BIOS compatibility again.

The framebuffer example depends on the VESA BIOS as well.

The 'bunch of lines' are likely related to the IOMMU being enabled.

Cheers, Philipp

Am 14.11.24 um 00:07 schrieb Lonnie Cumberland via l4-hackers:

...

Hello All,

I have been experimenting with L4Re and was able to compile the latest snapshot that seems to work well for almost all of the examples in QEMU from the "make qemu" menu which is a very good start, I think.

Lately, I have also used the "make grub2iso" which gives me the same menu of examples as the "make qemu" but for which it will generate an ISO of the example.

I generated ISO's for all of the examples and tested them on 3 different x64 computer systems which are all Intel with 2 being NUC's and 1 being a Dell XPS 8950 but when I boot any of the generated L4Re ISO's, it seems to boot all of the core modules but then gets to an error message that seems to be related to the video mode.

---

error: no suitable video mode found

And then the screen shows a bunch of lines.

I have been looking around though the L4Re code in the snapshot release, but I do not yet have a clue where how to change things so that these ISO's will boot completely on some hardware although things seem to boot up in QEMU.

I am thinking that there might just be some setting somewhere that I need to adjust, or something.

Any thoughts, suggestions, or ideas would be greatly appreciated.

Have a great evening, Lonnie

---

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Hi Lonnie, Martin,

to mimic the UEFI system in qemu you can do the following:

- find OVMF_CODE.fd, in my case: /usr/share/edk2/ovmf/OVMF_CODE.fd - compile the framebuffer example with `make efiimage E=framebuffer-example` (Code base: 2024.08 snapshot) - start qemu with: qemu-system-x86_64 -cpu host -enable-kvm -m 2G -smp 2 -serial stdio -bios /usr/share/edk2/ovmf/OVMF_CODE.fd -kernel images/l4re_framebuffer-example.efi

This gives me the serial output in the terminal and the nice morphing spectrum window within mag on the qemu screen.

Cheers, Philipp

Am 26.11.24 um 17:50 schrieb Martin Decky:

Dear Lonnie,

...

If it can be worked out in some way [..]

If you are targeting a native UEFI system, try the "efiimage" target that generates a binary that can be booted directly from UEFI (just make sure you boot the .efi file, not the .elf file). Or you can use the "chainloader" command if you already use GRUB 2 as your boot loader for UEFI.

The framebuffer example should use the GOP framebuffer and not rely on the VESA BIOS in this case.

If you also need an ISO image for UEFI, there is a patch upstream that provides the "grub2efiiso" target as a convenience [1] (not in the snapshot release yet).

[1] https://github.com/kernkonzept/mk/commit/ce9a28f474c2da4187a0c8f0ca2e43c288b...

Best regards

Martin Decky _______________________________________________ l4-hackers mailing list -- l4-hackers@os.inf.tu-dresden.de To unsubscribe send an email to l4-hackers-leave@os.inf.tu-dresden.de