I have an external HDMI monitor connected through a Thinkpad USB-C dock with a power button. The laptop is AMD 4750u T14 Gen 1.
When I suspend the laptop with the screen lid closed, and use the power button to turn it on, the external display works as expected.
However, if I suspend the laptop and then connect the USB dock and use the power button to turn on when the laptop lid is closed, the laptop turns on but the external display remain black (but other usb periherals work). As an extra step, I unplug and plug again (that is when the laptop is on but lid is still closed), then the external display(s) turn on.
I tried some udev level hacks with no success. Any suggestions?