ADL only works if a monitor i connected to the GPU

Question

I have a system with a discrete GPU, AMD Radeon HD7850, for computations only. The GPU has no monitor connected to it.

I would like to read fan speed and temperature from the GPU. This can normally be done with the ADL (AMD Display Library) API.

E.g. ADL_Overdrive6_FanSpeed_Get and ADL_Overdrive6_Temperature_Get. However, all ADL API calls return error when no displays are active, i.e. no monitor is connected.

How do I read these values when the GPU has no monitor connected to it?

The AMD Catalyst Control Center has the same problem, it too can't read the values when the display is inactive.

I know the values are accessible because I can find them with the HWiNFO64.

Answer 1

After consulting AMD and the guys behind HWiNFO64 I have learned that the only way to get these values from a headless GPU is to read them directly from the GPU registers.

To do this you need to write your own driver, since AMD doesn't make an API available.