Hi, I’m on R5 5600U, and I encounter the same suspend/resume issue with you.
When I use kernel 5.16.15-1 or 5.10.106-1 in dom0, with kernel parameters “iommu=soft” and “mem_sleep_default=deep”(whatever, I can’t recall it precisely), the suspension seems to work fine, but resume never brings it back to normal.
If I don’t login in tty1(lightdm) and switch to tty2, then echo mem into /sys/power/state to trigger suspend, I can come back to tty2. However, the system doesn’t work perfectly. If I try to switch back to tty1, the screen will turn black. If I type something into tty2, occasionally there will be some letters not showing correctly, showing "_"instead. Possibly because of some frame buffer issues.
However, in tty2 the system is basically “usable” (of course not in the form of daily, graphical use). Commands such as qvm-start or xentop is fully responsive.
Dmesg shows that , although my CPUs acclaim “firmware bug”, “mwait c-state 0x0 isn’t supported on this HW”, they are brought up by the system. And PSP along with amdgpu is working.