how to set X color depth at boot time?

[mda]

There is a "cheat code" for setting display resolution such as 1024x768,
but no boot code I see for setting color depth.
This is a problem for me, because I want to use 1024x768 but at that
resolution I only have 8-bit color.

Thanks.
-mda

[RockMumbles]

What do you have for a video card?

maybe try:

knoppix xmodule=vesa

I have some old cards that only work at 8bbp with the "normal" driver, but with the vesa driver they work with 16bbp.

rock

[mda]

I have an old thinkpad 770. It is supposed to be able to
go to 1024x768 at 16bit color, but was not with knoppix.

Setting xmodule=vesa did not help.

However, on a whim I tried fb1024x768 at boot, and inexplicably
I got 16bit color instead of 8bit, so I'm a happy camper now.
Who knows.....

[RockMumbles]

the fbsetups are pretty much for laptops (especially older ones), since they have problems with standard linux video.

rock

[mda]

this is an academic question at this point, but what has me confused
is that I thought that what the "vesa" X server module does is use
a linear frame buffer.
So how is it that the fbNNNN boot modes are working but xmodule=vesa
is not?

Is it just a question of different code paths in X?
Or are different kernels booted?
Or both?

-mda

[RockMumbles]

I don't know for sure either, but xmodule=vesa is running X normally except using the vesa module for graphic card support, instead of say nv for nvidea, ati for an ati card, etc..

When you first boot knoppix the opening screen is a framebuffer, X is not running at that point.

If you look into the syslinux.cfg file on a cd, boot floppy or hd install you can see how knoppix is started with the knoppix, fb800x600, and fb1024x768 startup commands.

rock