Re: setvbe command to set video mode

[Gerardo Richarte]

Vesa Jääskeläinen wrote:

> Gerardo Richarte wrote:
>  
>
> > I have implemented a new grub command (setvbe) which can be used to
> > switch the graphics mode before booting. It can take arguments like
> >
> >   setvbe 1024x768x32 (scans the video modes for a suitable one) (*)
> >   setvbe 0x118 (set mode 0x118)
> >
> > (*) it does not use the video mode list as used by vbeprobe because this
> > method doesn't work on some systems, specially on qemu.
> >    
>
> Have you tested this latest fixes in CVS?... I back ported quite a while
> ago some structure fixes to grub legacy that could be related.
>  
   I did try the latest changes (if you are talking about the 
off-by-one in a 179 bytes buffer (or 189, not sure). I think I reported 
that bug also.
   I don't perfectly recall the case, but qemu has a -std-vga command 
line argument, which forces some different features. I think 1024x768x32 
is only supported on this mode, and in this mode, the mode_list array 
(as used by vbeprobe) is empty, however, if you just scan all the modes 
and ask for information, the modes work (this is similar to what vbetest 
does, although it doesn't scan). And then, once you scanned the modes, 
the mode_array works fine (as far as I remember).

   So I finally chose to just scan the modes one by one, and not trust 
the mode_list, but this in my setvbe command. I haven't changed vbeprobe 
because I wanted to keep my changes as decoupled as possible, because I 
know that the GRUB team will not accept them, so I will have to port 
them to every new released version every time.

   gera