login window resolution

Mahadi Hasan tomahadi at gmail.com
Mon Mar 23 14:37:47 UTC 2009

There are a couple of ways that you can try, have a look at the
following which contains a few ways of doing what you want. I originally
posted it in another group, in an attempt to help a Windows user get
Ubuntu installed on his machine, which kept coming up in too high of a
resolution to be able to read the screen at boot up time.

Since I was writing to a green Windows user in that post, I included
lot of instructions on the use of sude, etc which you might already know
how to do, so skim over those parts if you already know them, and read
the parts about changing the boot up resolution which you are interested in.

For this firsat method, go to System, Administration, Start Up Manager
on the Ubuntu menu, and then to the
 > Boot Options tab of the resulting dialog. This tab allows me to choose
 > from resolutions anywhere from 600 x 480 to 1600 x 1200 and also
 > selections of 8 bit to 24 bit for color depth for the login screen.
 > Be prepared for a long wait while this program goes through it's
 > pre-configuration tasks, and post-configuration tasks when you start it
 > and exit it. I changed one option [resolution from 640x480 to 800x600]
 > and it kept running it's little progress bar animation back and forth
 > for the past ten minutes, so I got bored and closed it from the title
 > bar button.
 > OK, it took me a bit of spelunking to discover this, but grub [the boot
 > up manager] has an optional, not always there, configuration file at
 > /etc/default/grub which can specify the vga mode for the boot up screen
 > among other things. This can be set by the use of Start Up Manager, or
 > alternatively created with a text editor. I had to examine the grub
 > scripts to find this out. By examining the
 > /usr/share/pyshare/bootconfig/grub.py script file which determines the
 > resolution on start up I found the following information.
 > """Return the Grub vga code used, as an integer.
 > If no code is specified in the config, 769 is returned. [which is 640
x 480, 8 bits color]
 > Grub vga codes:
 > Colors 640x400 640x480 800x600 1024x768 1152x864 1280x1024 1600x1200
 > --------+----------------------------------------------------------
 > 4 bits |  ?             ?             770          ?
?               ?                 ?
 > 8 bits | 768         769         771          773
353           775            796
 > 15 bits | ?           784         787          790
354           793             797
 > 16 bits | ?           758         788          791
355           794             798
 > 24 bits | ?           786         789          792
?               795             799
 > 32 bits | ?           ?              ?              ?
356            ?                 ?
 > There is a setting in the /boot/grub/menu.lst file which specifies this
 > value, and evidently the previously mentioned /etc/default/grub is not
 > used, as I thought, even 'though the grub.py script looks for that
 > configuration file. So, according to menu.lst the following applies. -
 > ## lines between the AUTOMAGIC KERNELS LIST markers will be modified
 > ## by the debian update-grub script except for the default options below
 > ## DO NOT UNCOMMENT THEM, Just edit them to your needs
 > ## ## Start Default Options ##
 > And a ways further down from that is this section. Here you can set
the video resolution for the default kernel to be booted.

[Note that for 1024 x 768, 24 bits color mode, you should use vga=792 on
the defoptions line below.]
 > ## additional options to use with the default boot option, but not
with the
 > ## alternatives
 > ## e.g. defoptions=vga=791 resume=/dev/hda5
 > # defoptions=quiet splash vga=792
 > Here we see the vga mode being set for the default boot option, and one
 > # sign marks it as being in use, instead of being a comment like the
 > lines with two ##'s in the AUTOMAGIC section of the menu.lst file.
 > So... to change the default resolution used on your system during start
 > up,change the vga=nnn to the number representing the resolution you
want in
 > boot/grub/menu.lst, from the table previously pasted in above, and also
 > make sure that no /etc/default/grub file exists that could modify the
 > value to one you do not want.
 > I also note that it states in the grub.py file that if no code is
 > specified in the config it will default to the value vga=769 which
 > corresponds to 640x480, 8 bit colors. Further, to apply that
resolution to
 > all kernels installed and specified in the menu.lst file, instead of
 > just the default kernel, you would need to change the following section
 > of the AUTOMAGIC section to include the vga=792 setting as shown below,
 > and you would leave out the change to the defoptions section above,
 > which only applies to the default kernel in use.
 > ## default kernel options for automagic boot options
 > ## If you want special options for specific kernels use kopt_x_y_z
 > ## where x.y.z is kernel version. Minor versions can be omitted.
 > ## e.g. kopt=root=/dev/hda1 ro
 > ## kopt_2_6_8=root=/dev/hdc1 ro
 > ## kopt_2_6_8_2_686=root=/dev/hdc2 ro
 > # kopt=root=UUID=d87df8a8-9b0a-46c9-82ef-7c5503f46c62 ro vga=792

[once again, for a resolution at boot up of 1024 x 768 in 24 bit color
mode, use vga=792 on the configuration line above.]

There you go, three ways to set the resolution of your start up screen. 8-)

Later, Ray Parrish

It did not work.
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