Where is power_profile?

[Simeon Felis]

According to [1] I should be able to set the power profile, e.g. with:

echo "low" > /sys/class/drm/card0/device/power_profile

However I don't have this file:
root at arpa:~# echo "low" > /sys/class/drm/card0/device/power_profile
bash: /sys/class/drm/card0/device/power_profile: No such file or director

The directory structure looks like that:
root at arpa:~# tree /sys/class/drm/card0/
/sys/class/drm/card0/
├── card0-DVI-I-1
│   ├── device -> ../../card0
│   ├── dpms
│   ├── edid
│   ├── enabled
│   ├── modes
│   ├── power
│   │   ├── async
│   │   ├── autosuspend_delay_ms
│   │   ├── control
│   │   ├── runtime_active_kids
│   │   ├── runtime_active_time
│   │   ├── runtime_enabled
│   │   ├── runtime_status
│   │   ├── runtime_suspended_time
│   │   └── runtime_usage
│   ├── select_subconnector
│   ├── status
│   ├── subconnector
│   ├── subsystem -> ../../../../../../../class/drm
│   └── uevent
├── card0-SVIDEO-1
│   ├── device -> ../../card0
│   ├── dpms
│   ├── edid
│   ├── enabled
│   ├── modes
│   ├── power
│   │   ├── async
│   │   ├── autosuspend_delay_ms
│   │   ├── control
│   │   ├── runtime_active_kids
│   │   ├── runtime_active_time
│   │   ├── runtime_enabled
│   │   ├── runtime_status
│   │   ├── runtime_suspended_time
│   │   └── runtime_usage
│   ├── select_subconnector
│   ├── status
│   ├── subconnector
│   ├── subsystem -> ../../../../../../../class/drm
│   └── uevent
├── card0-VGA-1
│   ├── device -> ../../card0
│   ├── dpms
│   ├── edid
│   ├── enabled
│   ├── modes
│   ├── power
│   │   ├── async
│   │   ├── autosuspend_delay_ms
│   │   ├── control
│   │   ├── runtime_active_kids
│   │   ├── runtime_active_time
│   │   ├── runtime_enabled
│   │   ├── runtime_status
│   │   ├── runtime_suspended_time
│   │   └── runtime_usage
│   ├── status
│   ├── subsystem -> ../../../../../../../class/drm
│   └── uevent
├── dev
├── device -> ../../../0000:01:00.0
├── power
│   ├── async
│   ├── autosuspend_delay_ms
│   ├── control
│   ├── runtime_active_kids
│   ├── runtime_active_time
│   ├── runtime_enabled
│   ├── runtime_status
│   ├── runtime_suspended_time
│   └── runtime_usage
├── subsystem -> ../../../../../../class/drm
└── uevent

I'm running Arch Linux with uname -a:
Linux arpa 3.6.3-1-ARCH #1 SMP PREEMPT Mon Oct 22 10:23:56 CEST 2012
x86_64 GNU/Linux

lsmod | grep rad
ttm                    64384  1 radeon
drm_kms_helper         32877  1 radeon
drm                   218724  7 ttm,drm_kms_helper,radeon
i2c_algo_bit            5391  1 radeon
i2c_core               20707  5 drm,i2c_i801,drm_kms_helper,i2c_algo_bit,radeon

Syslinux boot command:
APPEND root=/dev/sda3 ro quiet splash init=/bin/systemd


Did the directory structure change? What am I missing?

Please CC me as I am not subscribed to the list. Thanks!



[1] http://www.x.org/wiki/RadeonFeature#KMS_Power_Management_Options