LM_Sensors For ATI Graphics Cards

Back in February, AMD's John Bridgman had expressed hope in providing LM_Sensors support for monitoring the GPU temperature and fan speed on ATI graphics cards. He was hoping to get the needed documentation to the LM_Sensors project in March, but that hadn't happened and currently AMD's focus is on open-source R600/700 series 3D support. However, interest in LM_Sensors support for ATI graphics cards has been rejuvenated on the sensor project's mailing list.

The mailing list discussion was started by a user interested in having LM_Sensors support for his ATI hardware. Hans de Goede, an LM_Sensors contributor, then responded that on at least some graphics cards the hardware monitoring IC is on the Radeon multimedia i2c channel. LM_Sensors doesn't yet have a driver supporting the Radeon multimedia i2c channel as with some hardware (the ATI All-In-Wonder was named) this channel is also used by the graphics card.

Kernel mode-setting though will actually come to the rescue now with the mode-setting being in-kernel and eliminating the need for any user-space component to be tapping the registers. The way now to support this i2c channel is by exposing it in the DRM driver and the LM_Sensors should recognize the hardware monitoring adapter.

Following the message from Hans, David Airlie (a Red Hat employee, xf86-video-ati developer, and the kernel's DRM maintainer) chimed in that fellow Red Hat employee Matthew Garrett is currently looking at adding this support.

The LM_Sensors support isn't here yet, but we'll be sure to write about it when it arrives.