bad opcode from vga/realemu on NUC7CJYH after UEFI boot

bad opcode from vga/realemu on NUC7CJYH after UEFI boot

[Silas McCroskey]

Have used these machines before without issue, so I think the
difference here is that I UEFI PXE booted this one rather than legacy
PXE booting it or legacy booting it from the root FS or USB.

Graphics come up in 800x600 mode during boot (I believe this is being
set by bootx64.efi, could try to set it differently there but haven't
figured that out yet), but when I try to resize to a larger size,
neither aux/vga -p nor aux/vga -m vesa -l 1600x1200x32 work; both
throwing the following error:

; @{aux/realemu; aux/vga -p}
bad opcode
000801 00004f00 00000000 00000000 00000000 00009000 00000000 00000000
00007bfa 0000 0000 0000 0000 csZoPdi 1000 63 ARPL [BX-6fd9], AX
aux/vga: write /dev/realmode: bad opcode

sysinfo posted at http://sysinfo.9front.org/src/312/body

Thanks,
sam-d

Re: [9front] bad opcode from vga/realemu on NUC7CJYH after UEFI boot

[cinap_lenrek]

there is no vesa bios on pure uefi systems (without CSM). so realemu
traps when executing all zero bytes as instructions.

bootx64.efi does not set any mode (yet). it queries the mode set up
by uefi firmware (according to the standard it is supposed to give you
the native resolution and it sais like at least 1024x768 but nope.
this is all pure sabotage to force you to install the windows driver
so they can stay resident on your machine and expose ther cooperate
branding).

anyway, your guessing is not too far off. we could actually add
code to 9boot to try to set a specific mode and hope that it maybe
work... i dont know how well this works or if they even let you do
that.

another way would be to use this grub operating system, which i think
can set specific graphics mode and load the plan9 kernel from that
as a multiboot kernel image.

or try to get the native driver to work. intel graphics is supported
(partially, not every models, but might not be hard to add support?)

good luck.

--
cinap

Re: [9front] bad opcode from vga/realemu on NUC7CJYH after UEFI boot

[Silas McCroskey]

Thanks, I'll take a look at those options. Think I'll start with
trying to get the native driver to work since I've never managed to
puzzle that out (always been content with vesa), so it'll be a good
exercise.

- sam-d

On Wed, May 6, 2020 at 10:08 AM <cinap_lenrek@felloff.net> wrote:
>
> there is no vesa bios on pure uefi systems (without CSM). so realemu
> traps when executing all zero bytes as instructions.
>
> bootx64.efi does not set any mode (yet). it queries the mode set up
> by uefi firmware (according to the standard it is supposed to give you
> the native resolution and it sais like at least 1024x768 but nope.
> this is all pure sabotage to force you to install the windows driver
> so they can stay resident on your machine and expose ther cooperate
> branding).
>
> anyway, your guessing is not too far off. we could actually add
> code to 9boot to try to set a specific mode and hope that it maybe
> work... i dont know how well this works or if they even let you do
> that.
>
> another way would be to use this grub operating system, which i think
> can set specific graphics mode and load the plan9 kernel from that
> as a multiboot kernel image.
>
> or try to get the native driver to work. intel graphics is supported
> (partially, not every models, but might not be hard to add support?)
>
> good luck.
>
> --
> cinap