A number of M1 Mac mini users have been sharing issues with displays not waking up when waking up the Mac from sleep. The expected result when the M1 Mac mini is waken up from sleep is for the display to turn on instantly, however, this is not the case for some users.
M1 Mac mini not waking up your display? You are not alone
Apple has showcased the M1 chip‘s performance by showing how fast MacBooks wake up from sleep when the lid is opened up. In case you missed the event, the MacBook woke up instantly, as fast as an iPhone or iPad when the power button is pressed. However, something does not seem to be working right for users who have the M1 Mac mini as they have been reporting the issue where the display shows weird colors instead of waking up properly. As per a thread on MacRumors forums:
My M1 (8gb/256) Mac mini doesn’t seem to want to wake my displays after its been sleeping. I have tried with 2 different displays with 2 different HDMI cables with the same thing occurring on each one. I am currently only using one at a time. I also noticed some pink squares/graphics glitches on the Big Sur boot/log in screen (with the coloured background, not the black and white boot up).
Some users have reported the same issue but said that switching from a Thunderbolt 3 cable to an HDMI cable fixed the issue for them, however, the user who started the thread reported the issue while using an HDMI cable. Although it is possible that some users might be seeing the issue due to faulty cables, there are many users who also report that they don’t see the issue at all.
A user updated in the forums yesterday that an Apple Support technician had been looking into the issue, and told them that a fix will be coming in a future macOS Big Sur update. Apple is currently working on macOS Big Sur 11.3 beta, so it is possible that a fix might be included in the final release, which should be out in a few weeks.