Re: kernel goes dark on boot

[Jared McNeill <jmcneill%invisible.ca@localhost>]

After calling ExitBootServices(), the only things that work are UEFI 
runtime services. You'll have to find another way to print to the console.

On Mon, 20 Feb 2023, Emmanuel Dreyfus wrote:

> On Wed, Jan 11, 2023 at 08:30:20AM +0000, Emmanuel Dreyfus wrote:
> > An interesting problem on an all-in-one HP PC. Booting
> > NetBSD-10.0_BETA/amd64 (or prior versions) works fine until the
> > kernel starts displaying its messages. At that point the screen
> > turns dark.
>
> I patched bootx64.efi to comment out the vbe_commit() call,
> the screen does not go dark, but system still crashes.
>
> By commenting out the uefi_call_wrapper() for ExitBootServices
> I can printf up to the startprog64() call, then the bootstrap
> jump into assembly code, and it is much more difficult
> to figure what is going on. All I can say is that startprog64()
> arguments do not look insane.
>
> I am looking for debug hints. Is there some sample code somewhere
> that calls UEFI Print method from assembly? Any other suggestion?
>
> --
> Emmanuel Dreyfus
> manu%netbsd.org@localhost