emerge -Dp  xorg-server shows
 :
[blocks B     ] x11-drivers/ati-drivers (is blocking x11-base/xorg-server-1.4-r2)
[blocks B     ] x11-misc/xkbdata (is blocking x11-misc/xkeyboard-config-1.1)
[blocks B     ] x11-misc/xkeyboard-config (is blocking x11-misc/xkbdata-1.0.1)
[blocks B     ] <sys-apps/baselayout-2.0.0_rc (is blocking sys-apps/makedev-3.23.1)

emerge -Dp ati-drivers shows

[blocks B     ] x11-drivers/ati-drivers (is blocking x11-base/xorg-server-1.4-r2)
[blocks B     ] x11-misc/xkbdata (is blocking x11-misc/xkeyboard-config-1.1)
[blocks B     ] x11-misc/xkeyboard-config (is blocking x11-misc/xkbdata-1.0.1)
[blocks B     ] <sys-apps/baselayout-2.0.0_rc (is blocking sys-apps/makedev-3.23.1)