I have an iMac mid 2010 ( Clarkdale i3 540 and Radeon 4570m )
This seems to be a common issue with apple running linux . The system goes to sleep but the backlight is still on ( with black screen/ no image) I think its a GPU issue . I am running the standard linux drivers , no third party drivers
Also the backlight is not adjustable, the hotkeys do not respond .
Running various versions of Ubuntu, currently Ubuntu Mate Release 24.04.2 LTS (Noble Numbat) 64-bit
Kernel Linux 6.11.0-25-generic x86_64
Any suggestions