zzfrom:http://www.ydl.net/support/solutions/ydl_6.x/video-config.shtml
Introduction
The PS3 is both a game console and a computer. Game consoles traditionally output to TV screens, computers traditionally output to computer monitors. TV screens and computer monitors have very little in common. The PS3 can output to both, and can also output to High-Definition (HD) TV screens. Since this involves several completely different sets of standards, things can get complex. This HOWTO will show you how to make your selected PS3 video mode permanent.
Boot configuration
Once you have determined the video mode you find best for your monitor or television, you may make the change more permanent by editing your /etc/yaboot.conf file, adding a configuration with the video argument you would like. The following is an example yaboot.conf created by the YDL system installer when using video mode 1080i to install YDL:
# yaboot.conf generated by anaconda
boot=/dev/ps3da
init-message=Welcome to YDL!\nHit for boot options
partition=1
timeout=80
install=/usr/lib/yaboot/yaboot
delay=5
enablecdboot
enableofboot
enablenetboot
nonvram
mntpoint=/boot/yaboot
usemount
image=/vmlinux-2.6.23-9.ydl6.1
label=linux
read-only
initrd=/initrd-2.6.23-9.ydl6.1.img
append="video=ps3fb:mode:4 rhgb quiet root=LABEL=/1"
You should change the number mode in the append line to match that which is supported by your TV, refer to
PS3 video mode introduction. For example if I wanted to run my PS3 in 720p mode I would change the above append line to: append="video=ps3fb:mode:3 rhgb quiet root=LABEL=/1"
When you reboot, it will use this video mode.
This HOWTO was written by Tim Renner and David Seikel, Terra Soft Solutions.