Basic power management for radeon (dynpm)

As I know there isn't power management (radeon cards). See PR 194966 and FreeBSDwiki/Graphics:

Radeon video cards:
  • AGP cards not supported before FreeBSD 10-CURRENT
  • Features not yet working/implemented:
    • Hardware-assisted video decoding
    • Audio over HDMI or DisplayPort
    • Multiple cards sharing output connectors
    • Power management

The hit on mailing list describes you should apply the patch. Did you apply and rebuild?
Yes i also notice that :) i dont know how to apply the patch or has been applied thats why i post here,I m trying maybe i find something, I use FreeBSD on servers mostly as for Desktop is secondary hobbyist i think there is something to do with the kernel module parameter maybe a simple command on loader.conf and load some kind of firmware can fix the problem
on linux its this
i dont know how to apply the patch or has been applied
You should download the FreeBSD's source (if you don't have in /usr/src) and extract it. After it you should download the patch.
After it:
cd /usr/src
patch -Np1 < /where/the/patch/located/radeon-pm-profile.diff
make buildworld
Maybe you haven't to make buildworld and it's enough to build the radeon module - I did it ( make buildworld) only one time, several years ago. Maybe you want to read 23.5. Updating FreeBSD from Source section.
Seems that the DragonflyBSD version is doing well in graphic cards it is sync with linux 3.18 i still testing..