Driver API and source code available in liquidctl.driver.corsair_hid_psu.
It is necessary to initialize the device once it has been powered on.
# liquidctl initialize
The +12V rails normally functions in multiple-rail mode, and initialize will by default reset the PSU to that behavior. Single-rail mode can be optionally selected by passing --single-12v-ocp to initialize.
The PSU is able to report monitoring data about its own hardware and basic electrical variables for the input and output sides.
# liquidctl status
Corsair RM650i
├── Current uptime 3:43:54
├── Total uptime 9 days, 11:43:54
├── Temperature 1 50.0 °C
├── Temperature 2 40.8 °C
├── Fan control mode Hardware
├── Fan speed 0 rpm
├── Input voltage 230.00 V
├── +12V OCP mode Multi rail
├── +12V output voltage 12.12 V
├── +12V output current 7.75 A
├── +12V output power 92.00 W
├── +5V output voltage 4.97 V
├── +5V output current 2.88 A
├── +5V output power 14.00 W
├── +3.3V output voltage 3.33 V
├── +3.3V output current 1.56 A
├── +3.3V output power 5.00 W
├── Total power output 110.00 W
├── Estimated input power 124.00 W
└── Estimated efficiency 89 %
Input power and efficiency are estimated from efficiency data advertised by Corsair in the respective HXi and RMi PSU user manuals.
The fan speed is normally controlled automatically by the PSU. It is possible to override this and set the fan to a fixed duty value using the fan channel.
# liquidctl set fan speed 90
This changes the fan control mode to software control and sets the minimum allowed duty value to 30%. To revert back to hardware control, re-initialize the device.
HXi and RMi power supply units do not report input power or current to the host. Yet, the efficiency data in the user manuals can sometimes result in more conservative estimates that the input power and efficiency values iCue and CorsairLink display.1
We believe that this is the result of the use, in those programs, of a different set of efficiency curves, based on internal and unpublished testing. Additionally, the manuals also do not match publicly available data submitted for the 80 Plus certification of these PSUs.2 Unfortunately, the latter is only available for 115 V input.
At this point it is important to remember that efficiency, and consequently power draw, are functions of more than just the total power output. Thus, the data in the user manuals is probably significantly less precise than it appears to be, and we believe the same could be true for the values displayed by iCue and CorsairLink.
Still, we encourage Corsair to make more of its efficiency data public, which would hopefully allow liquidctl to present more precise estimates.
1 See comments in issue #300.
2 Available at 80 PLUS® Certified Power Supplies and Manufacturers.