A nuisance issue that appeared in 12.0 and continues in 12.1.
Suspend/resume basically works fine, but the system hangs for 20 seconds between
iwn0: iwn_read_firmware: ucode rev=0x09dd0401
uhub0: <Intel EHCI root HUB, class 9/0, rev 2.00/1.00, addr 1> on usbus0
Running 11.x, resume was very quick.
I'm not too concerned about it, but maybe investigating this issue will uncover solutions for more serious problems. One more data point...
Is there any chance you can bisect between the fast and slow versions?
(In reply to Ed Maste from comment #1)
Yes, but not real soon. I have to finish up some projects, after which I can try an 11.3 install on a spare disk.
For now I'll add that I don't see this behavior on a ThinkPad T61 (which also uses iwn) or ThinkPad X120e (rtwn).
I should have an 11.3 install running shortly.
What specific info should I provide?
Homed in on the issue by disabling all non-essential modules in /boot/loader.conf and services /etc/rc.conf, which alleviated the issue, then restoring them one by one.
The delay appears to be tied to kernel frequency.
I had set kern.hz=100 in loader.conf to extend battery life. I've been doing this on laptops and it has never had a negative impact, until I upgraded to 12.x on the ThinkPad X201.
After removing this and restoring all other modules and servies, the delay is about 2 seconds rather than 20. So increasing the kernel frequency by a factor of 10 (default is 1000) reduces the delay by a factor of 10.