SDB: Configuration of VESA-Framebufferdevice (since XFRee 4.0)

Configuration of VESA-Framebufferdevice (since XFRee 4.0)

Support knowledgebase (cg_framebuffer-x4.0)

Applies to

SuSE Linux: Versions since 6.4
XFree86: Versions since 4.0

Request:

You have a graphic card which is not supported with XFree86-4.0 directly. Anyhow you want to use the graphical user interface X.
You want to use a textmode with high resolution e.g. 160x64.
You want the little penguine bootlogo during the bootprocess to be displayed ;-)

Idea

Before the official start of the kernel, even before the kernel switches into the 32 Bit protected mode, you can change with a Bios call to the graphic mode you want to use. This graphic mode will be in use during the linux system is running.

Requirements

Your graphic card is compatible to `VESA BIOS Extensions 2.0' or higher.

Procedure:

To put the facts mentioned above in practice you need the kernel support for the so called framebufferdevice. If you intent to use X also with the framebufferdevice, due to the fact that your graphic card is not supported with XFree86 directly, you have to install a package from the CD. Since SuSE Linux version 6.3 the support for VESA framebufferdevices is compiled into the kernel, so that it is not neccessary to compile the kernel new.

The procedure step by step

Choose the resolution and colour depth that you want to use out of the table below. Boot your system and at the LILO prompt type in the bootparameter 'vga=x'. Please notice at this point that at this stage of the bootprocess you have an international keyboard. The value "x" pick out of the table, please


    Resolution in Pixel

colour depth     | 640x480  800x600  1024x768 1280x1024
256        (8bit)|  769      771       773      775
32000     (15bit)|  784      787       790      793
65000     (16bit)|  785      788       791      794
16.7 Mill.(24bit)|  786      789       792      795

To get a resolution of 1024x768 with 16 Bit colour depth 
you have to type at the LILO boot prompt the following 
option:

linux vga=791

This should look like this:

boot:linux vga=791

Please consider that your graphic card may not support all resolutions.
The kernel switches immediately during the start in the opted graphic mode. You can see in the top left corner a little penguine logo.
To set this mode to default, please edit the file /etc/lilo.conf with your favourite editor and change the entry vga=normal into the desired mode e.g. vga=791.
After saving the file execute the command
```
lilo
```
If, after rebooting the system, the new mode is not active, please check if the right boot-device has been entered in /etc/lilo.conf.

Configuration of the framebuffer with SaX2

Proceed the configuration of the framebuffer with SaX2 as described below. Start SaX2 with the command
```
sax2 -m 0=fbdev
```
SaX2 now starts directly with the driver for the framebufferdevice. In case that the mouse operates, you have got the possibility to confirm in this dialogue the first suggestion with "ok". Otherwise you can choose the adequate mouse and keyboard configuration in the SaX2 dialogue.
Attention should be paid to to the fact that there is no possibility to change the display parameters using the framebufferdevice. After the configuration Start X with the command
```
startx -- -bpp 16
```
The parameter `-bpp' also states the wanted colour depth. This colour depth has to coincide with the colour depth that was chosen during the start of linux using the `vga'-option.

Keywords:

SDB-cg_framebuffer-x4.0, Copyright SuSE Linux AG, Nürnberg, Germany - Version: 30. Mär 2001
SuSE Linux AG - Last generated: 13. Dez 2001 by ast (sdb_gen 1.40.0)