Re: [9front] Booting EFI (or work-arounds to install 9front on GPT partition)?

[Jens Staal <staal1978@gmail.com>]

On Saturday 06 December 2014 12:19:04 you wrote:
> we currently have no gpt support in fdisk. but mischief is working
> on it.

Thanks. Looking forward to it :)

> 
> from the description, it seems the efi loader has some problems.
> i assume the "some sort of shell" refers to the boot console (see
> 9boot(8)). in one case, it seemed to be unable to locate the kernel
> file from the boot media.
> 
> the bootloader; as a last action; prints "boot" before jumping to the
> kernel. if that just hangs, it means the kernel fails *before* it is
> able to attach to the GOP framebuffer.
> 
> possible causes (speculation):
> 
> - bad memory map (see *e820= boot parameter)
> - efi doesnt provide GOP (see *bootscreen= boot parameter)
> - maybe kernel image got corrupted (in memory?) due to wrong assumtptions
> - you might have tried to load an older kernel that has no *bootscreen=
> support - acpi?
> 
> what we can do to get some evidence:
> 
> hit any key on boot to get to the bootloader console (until you see the
> ">" prompt).

I did see that prompt in one of my combinations - I will have to check again. 
I think it was when I booted the CD in EFI mode.

> 
> then read what boot parameters where established by the loader:
> *e820=, *bootscreen=, and *acpi=
> you can use the "show" command to print the boot parameter environment.
> 

great! That will definitely help. I will get back to you when I have checked 
it.

> you can try serial console by specifying console=0 before booting the
> kernel. that way, we might see more early output of the kernel.
> if thats not an option, then all we can do commenting out code before
> bootscreeninit() in the kenrel to figure out where it fails.
> 

so I can write console=0 in plan9.ini on my bootable USB and this info will be 
available?

> the efi loader has pxe boot support. so you might be able todo the
> debugging this way without having to copy stuff to usb or burn cdroms.
> 
> keep in mind that the efi stuff is very fresh and has only been tested
> with thinkpads and qemu/vmware and vbox so far. it would be good to
> know what kind of machine this is.
> 

I noticed that the previous reply only got to mischief (now forwarded to list) 
with details about the machine.

In a way, if (in the future) the installer booted in BIOS mode still can do a 
GPT install, fighting with booting the install media in EFI mode is not that 
critical. That could then be dealt with afterwards as long as one can 
configure an "efi install" (no mbr, efi boot files installed in ESP 
partition...).

A question about an "efi install" - I suppose that 9fat then will point to the 
ESP partition? Will it understand or default to something like EFI/boot/Plan9/ 
so that it can nicely co-exist with other OSes?

> --
> cinap