If you have a notebook with an Intel video card, probably you’re using 915resolution to set up your resolution correctly at Xorg (or, if you’re not using it, probably you’re facing problems changing resolution at Xorg).
But, you don’t need this anymore 🙂 , just install the newest Intel video driver at Gentoo to see everything working normally again (without any hack).
The ebuild is named x11-drivers/xf86-video-i810 . Just unmask it (keywork ~x86) to get the version 2.0.0.
After installing it you’ll see your X configuration working normally again 🙂
Thanks Daniel for this tip!