I think there is another issue with suspend resume & HDMI.
Another S905X2 user say the same, power off resume is working, suspend resume -> black screen.
So I guess it wake up as the wake up function is same for power off & suspend but you don’t see anything on the TV. On a power off and resume the HDMI interface get initialized again so this is the reason why you see the resume on TV.
I will see if I can reproduce with my TV.
What TV, brand, type you have?
EDIT: I just checked it with the power button:
One press, kvim3 power off, second press wake-up
Sending the kvim3 to suspend, wake-up with IR is working, power button not.