Introduction
You may find that while the Yellow Dog Linux v3.0 installer was able to utilize your graphics card and monitor in a pleasing graphics mode, post-installation your GUI environment is not set properly or X is not starting at all.
This is likely due to the fact that the Installer defaults to what is called "fbdev" which is the "frame buffer device" driver, a default mode of operation for the graphics card that. While not capable of the same advanced capabilities of the native driver (eg: "ati"), "fbdev" works with nearly all combinations of cards and monitors and is a good starting point for less than desirable graphics modes.
Here we go ...
You need to first run a program that will reset your configuration to something similar to that which was used during Installation.
- Set your system to default to a shell
CTRL-OPTION-F2
(login as root)
pico /etc/inittab/ [ENTER]
(roughly a dozen lines from the top, modify "id:5:initdefault:" to "id:3:initdefault:")
CTRL-X (exit and save)
reboot [ENTER]
... this resets your computer to default to a command line environment instead of automatically starting X. Once you get the graphics settings modified to your liking, you can change the '3' back to a '5', reboot, and you will be greeted with a graphical login once again.
- Reset to default configuration
Xautoconfig [ENTER]
startx [ENTER]
... there are three things that may have occurred:
If you see pretty colors and at least 640-480, then we are doing well -- jump to 3 below.
If you see really funky colors (pinks and blues, appears to be inverse) then we may need to experiment a bit -- jump to 4 below.
If X did not start, then we definitely need to experiment -- jump to 5 below.
- Adjust resolutions
You can manually adjust the default resolution of your display. This assumes you have at least 16-bit color depth (pretty colors), as described in 2 above.
From the same shell, as root:
pico /etc/X11/XF86Config [ENTER] (look for)
Section "Screen" Identifier "Screen0" Device "ATI Rage 128" <-- example only Monitor "Monitor0" DefaultDepth 16 SubSection "Display" Depth 16 Modes "640x480" <-- here EndSubSection EndSection
... where the Modes may be higher, such as "1024x768". Determine the maximum resolution that your monitor is capable of (might want to check Apple's website, Google.com, or the Yellow Dog Linux Hardware Support pages for this information.
You may adjust the resolution, save, exit 'pico' and then:
startx [ENTER]
... if it works to your liking, you are good to go. If not, you may continue to experiment. If you really mess-up the file, you can always re-run Xautoconfig to get back to the default settings.
- Adjust color depth
You can manually adjust the color depth of your display. This assumes you have at least X running, even in ugly mode, as described in 2 above.
From the same shell, as root:
pico /etc/X11/XF86Config [ENTER] (look for)
Section "Screen" Identifier "Screen0" Device "ATI Rage 128" <-- example only Monitor "Monitor0" DefaultDepth 16 <-- here SubSection "Display" Depth 16 <-- and here Modes "640x480" EndSubSection EndSection
... where the 'DefaultDepth' is actually a pointer, telling the system to attempt to use the settings beneath the same number, below. You may adjust both numbers to 16, 24 or even 32 where 32 is the highest setting possible and represents millions of colors, even more than the human eye can perceive. Typically, 16 or 24 is very nice, and faster.
You may adjust the color depth, save, exit 'pico' and then:
startx [ENTER]
... if it works to your liking, you are good to go. If not, you may continue to experiment. If you really mess-up the file, you can always re-run Xautoconfig to get back to the default settings.
- Modify the graphics card driver
You can manually invoke a different graphics card driver, a piece of code that tells the graphics card how to talk to the computer and monitor. It is sometimes the case that you will need to replace the driver usually associated with the given card with the "frame buffer driver". The 'fbdev' driver uses a base-line, but functional set of instructions unique to PowerPC computers and their associated firmware.
From the same shell, as root:
pico /etc/X11/XF86Config [ENTER] (look for)
Section "Device" # no known options #BusID Identifier "ATI Rage 128" Driver "ati" <-- here, example only VendorName "ATI Rage 128" BoardName "ATI Rage 128" EndSection... where the "ati" will be replaced with "fbdev". Once modified, save, exit 'pico' and then:
startx [ENTER]
... if it works to your liking, you are good to go. If not, you may continue to experiment, but truly, if your resolution is 640x480 and the Driver is 'fbdev' and you cannot start X, I suggest you test the same hardware under Mac OS, check all cables, make certain the graphics card is original to the computer, and finally, try a different monitor.
- Modification from the graphical environment
Once X is starting, running, and displaying in a fashion that is useable, even pleasing, you may experiment further through the use of the Display settings:
Yellow Dog menu --> System Settings --> Display
NOTE! that any modification to these settings will override the work you have done within the XF86Config file. You therefore may desire to first back-up your work, as follows:
cp /etc/X11/XF86Config /etc/X11/XF86Config.backup [ENTER]
... and if you need to recover your backup, logout of the graphical environment, then:
mv /etc/X11/XF86Config.backup /etc/X11/XF86Config [ENTER]
- Adjust resolutions
This HOWTO was written by Kai Staats, Terra Soft
