I noticed that in the "ACPI support" in the gentoo-sources 2.6.15-gentoo-r7 there is not the option to activate "Sleep States" which is in the vanilla-sources 2.6.15.1. Can you enable that option please?
Uhm, definitely not missing here... you should attach your kernel .config.
Created attachment 82110 [details] My kernel configuration Here's my kernel configuration.
Created attachment 82112 [details] This is the screenshot of menuconfig This is a screenshot which shows that the option "Sleep states" is missing...
In future, please use the search feature: In menuconfig, type /SLEEP<enter> You'll note that !SMP is a dependency of ACPI_SLEEP, which means that Sleep states is not available for SMP systems. If you feel that it should be, please file a bug upstream or write to the linux kernel mailing list.