[gentoo-user] about the vga clause on kernel line of grub.conf

[gentoo-user] about the vga clause on kernel line of grub.conf

[Harry Putnam]

For quite a long time I've been using things like:
  vga=0x31A

On the kernel line in grub.conf

Its a hexidecimal system drawn info in this (partial) chart I found
somewhere in the kernel documentation long ago.

   ##      640x480 800x600 1024x768 1280x1024
   ##   256 0x301   0x303   0x305    0x307
   ##   32k 0x310   0x313   0x316    0x319
   ##   64k 0x311   0x314   0x317    0x31A
   ##   16M 0x312   0x315   0x318    0x31B

I've used kernel lines like below in grub.conf:
                                  (asterisks added)
  kernel /vmlinuz  root=/dev/hda5  ** vga=0x31b **  video=vesfb:mtrr:3,ywrap

For a very long time. (On occasion I've needed a smaller resolution
and used 0x317)

But on two recent installs of gentoo as vmware guests, that kind of
entry isn't doing any good and I'm still being prompted to make a
choice. 

When I hit <enter> as directed a largish chart of what look to be
octal based settings, flashes by and only the last portion of it
remains visible.

It has choices like 340, 341 and many other three digit offerings from
a large chart that shows the resolutions you get with the 3 digit
choices.

I was unable to find this chart by grepping in the kerne//Documentation
directory. 

Where does the boot process access that chart?

And why is it that the hex system is ignored and this other system
offered at boot?

I'm successfully using the hex system on my main gentoo machine... but on
the two recently installed gentoo vmware guests it doesn't work.

It may be relevant that these installs are console only... no X.

Re: [gentoo-user] about the vga clause on kernel line of grub.conf

[Paul Hartman]

On Tue, Mar 2, 2010 at 4:55 PM, Harry Putnam <reader@newsguy.com> wrote:
> For quite a long time I've been using things like:
>  vga=0x31A
>
> On the kernel line in grub.conf
>
> Its a hexidecimal system drawn info in this (partial) chart I found
> somewhere in the kernel documentation long ago.
>
>   ##      640x480 800x600 1024x768 1280x1024
>   ##   256 0x301   0x303   0x305    0x307
>   ##   32k 0x310   0x313   0x316    0x319
>   ##   64k 0x311   0x314   0x317    0x31A
>   ##   16M 0x312   0x315   0x318    0x31B
>
> I've used kernel lines like below in grub.conf:
>                                  (asterisks added)
>  kernel /vmlinuz  root=/dev/hda5  ** vga=0x31b **  video=vesfb:mtrr:3,ywrap
>
> For a very long time. (On occasion I've needed a smaller resolution
> and used 0x317)
>
> But on two recent installs of gentoo as vmware guests, that kind of
> entry isn't doing any good and I'm still being prompted to make a
> choice.
>
> When I hit <enter> as directed a largish chart of what look to be
> octal based settings, flashes by and only the last portion of it
> remains visible.
>
> It has choices like 340, 341 and many other three digit offerings from
> a large chart that shows the resolutions you get with the 3 digit
> choices.
>
> I was unable to find this chart by grepping in the kerne//Documentation
> directory.
>
> Where does the boot process access that chart?
>
> And why is it that the hex system is ignored and this other system
> offered at boot?
>
> I'm successfully using the hex system on my main gentoo machine... but on
> the two recently installed gentoo vmware guests it doesn't work.
>
> It may be relevant that these installs are console only... no X.

From linux/Documentation/svga.txt:

   **  Short intro for the impatient: Just use vga=ask for the first time,
   **  enter `scan' on the video mode prompt, pick the mode you want to use,
   **  remember its mode ID (the four-digit hexadecimal number) and then
   **  set the vga parameter to this number (converted to decimal first).

HTH :)