Re: Choosing grub2 video modes

[Andrei Borzenkov]

В Thu, 11 Jun 2015 11:19:38 -0400
Alex Regan <address@hidden> пишет:

> Hi,
> 
> >> I'm confused about how to control the text video mode from grub. I've
> >> seen references to GRUB_GFXMODE and gfxmode, but I don't understand how
> >> it's set.
> >>
> >
> > gfxmode is interpreted by gfxterm console driver when it starts. If you
> > are using plain console, it has no effect. To change resolution during
> > run-time you would probably need to switch console driver to something
> > else (see terminal_output command) and then back.
> >
> >> I've tried setting it using "set gfxmode=640x480" in
> >> /boot/grub2/grub.cfg and other variations, but they seem to be ignored.
> >>
> >
> > This must be done before output is switched to gfxterm.
> >
> >> I've tried setting GRUB_GFXMODE=640x480 in /etc/default/grub then
> >> recreating grub.cfg, but that also doesn't appear to work.
> >>
> >
> > You need to use GRUB_TERMINAL_OUTPUT=gfxterm for this to have any
> > effect. Or load gfxterm manually in grub.cfg or at run-time.
> 
> I must not be understanding, because I've made a few other changes and 
> it still doesn't work. Can you check my /etc/default/grub file and see 
> what further changes need to be made?
> 

I think there is some confusion here. As was already asked - are you
speaking about video mode in GRUB itself or in Linux kernel after it is
booted?

> GRUB_TIMEOUT=5
> GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
> GRUB_DEFAULT=saved
> GRUB_DISABLE_SUBMENU=true
> GRUB_TERMINAL_OUTPUT=gfxterm
> GRUB_TERMINAL=gfxterm
> GRUB_CMDLINE_LINUX="rd.md.uuid=bde3f430:15091bce:874aaa0e:e48f341a 
> rd.md.uuid=921fb4bb:6329d29b:734b1584:7f4d3dba "
> GRUB_DISABLE_RECOVERY="true"
> GRUB_GFXMODE=800x600x32
> GRUB_GFXPAYLOAD=800x600x32
> GRUB_GFXPAYLOAD_LINUX=800x600x32
> 
> When booting, it also prints some kind of "error" message but it goes to 
> fast to see what's being printed. Is this info saved anywhere, or is it 
> possible to store it or pause it to view? Or perhaps you can identify it 
> from some incorrect setting in the file?
> 
> I'm pretty much grasping at straws now because there is just so much 
> information, so much has changed, and there seems to be no definitive 
> resource that explains this in context.
> 
> Thanks so much.
> Alex