GRUB2 no vbe_mode_info in UEFI

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TheMastermaind
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GRUB2 no vbe_mode_info in UEFI

Post by TheMastermaind »

Dear Community!

I am writing a small C++ based kernel as a hobby project.
Currently its 32-bit (x86) but it will expanded to 64-bit soon.
I use GRUB2 as my bootloader to boot my multiboot compliant kernel. For emulation I use qemu with efibios and real efi hardware.

Now the problem is that GRUB2 somehow doesnt pass any vbe info in multiboot structure. I request vbe via the multiboot flags in my bootstrap assembly and qemu seems to switch the mode but those structures are empty.
Is it due to the use of (u)efi and GOP or is it a bug?
If its because of efi then how can i make use of the GOP framebuffer in my kernel?
If its a bug how can i work around this? Or which bootloader you can suggest then?

Thanks in advance
TheMastermaind.
jnc100
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Re: GRUB2 no vbe_mode_info in UEFI

Post by jnc100 »

Have you tried asking for a framebuffer info (type 8 ) tag instead? I'd imagine it doesn't supply a vbe tag because it used GOP to set the video mode, so cannot give you any information about vbe mode numbers or vbe protected mode interfaces simply because it hasn't even tried to use it.

Regards,
John.
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