[LinuxBIOS] linuxbios + xf86-video-unichrome: no VGA BIOS needed.

Stefan Reinauer stepan at coresystems.de
Sat Mar 17 16:29:50 CET 2007

* Luc Verhaegen. <libv at skynet.be> [070317 15:39]:
> Are you saying there that, for the likes of filo, grub, etherboot, etc 
> will be forced to set up a full VGA console themselves? 

Not more than at the moment. You need functions that write characters to
0xb8000, more or less. But you need them in v2 as well. LinuxBIOSv2 does
not provide a library or anything for console output.

> Or are you for 
> forcing everybody to use a serial console to:
> * instruct the bootloader on what to do, what kernel to load from where.
> * manually fsck your root filesystem after a bad reboot.
> * or in the most insane case: alter your X setup when X gives up?

Noooo! ;-) No worries. This is only for everything up to loading the
payload. The bootloader (payload) will be able to use an initialized
VGA console (and, eventually find out via the linuxbios table whether it
is text mode or framebuffer and what address and resolution it is?)

> I understand that this is all happening too late for debugging 
> linuxbios, but this isn't about debugging linuxbios. For me it is about 
> being able to do something useful when it jumps to the bootloader or the 
> kernel. When you force everybody to have serial for this, linuxbios will 
> not be accepted by the masses, even when their full board is directly 
> supported.

The idea is just to hide the _LinuxBIOS_ _debug_ messages from VGA
console, as it is too late for debugging. In my tests FILO would
immediately start printing the grub menu in text mode, but that is the
first thing you will see, after a fraction of a second.

> Now i'm not overly keen on spending time on a bootsplash myself, it is 
> something everyone can quite easily live without. But in previous 
> conversations i don't remember you being negative towards it :)
It is one thing I found out during the last few days, starting to work
on vm86/x86emu: In v3 we are so fast again that the need of a bootsplash
during _LinuxBIOS_ execution might not exist. Maybe the payload should
do this, or the CMOS setup menu (to be shown while waiting for the
keypress timeout), that some people talked about,.. or....

I am not at all negative. I am just thinking out loud where stuff is
done best.

> I fully understand that you want to push this as far down the linuxbios 
> line as possible. But it would be nice if linuxbios presented a working 
> vga console to the actual payload. 

It does this, but in v3, it will not use it anymore for printing "all
devices initialized. looking for payload. etc pp".

Well, v3 currently knows how to init the VGA console by executing an
option rom, but we will be changing this soon, I hope (for instance when
bringing the Epia port over)


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