It is handy we both have N100 or the differences would make things less certain.
The N100 southbridge where my USB interface lives is integrated… I don’t have any expanded IO at all. Just the standard 4x USB3.2 Gen 2 (10Gbps), and I have nothing else plugged in except a combination keyboard/mouse.
I am running x64 Debian 12.6.
16GB DDR4
512GB SSD in M2 slot.
Standard Gigabit LAN, no WiFi.
It’s a “Trigkey Green G4”… easily found on amazon and elsewhere.
BIOS settings are all as it came… nothing messed with.
It is running now… velbus (test rig, just 4 modules) connected, minicom -H -w running to ttyACM0… PowerTOP is open and refreshing in another console and shows everything pretty firmly settled in C10 over 99%. Power consumption at the wall is a pretty steady 9W.
I am out of ideas :-/
I can get C10 down to 80% if I make the velbus busy by sending lots of button presses. Some of that could be the terminal handling though.
How super weird, huh. Getting the entire package be asleep for 99% of the time sounds really amazing – this would be almost as good as putting the machine to S3 sleep. Best I’ve seen was, like, pc10=92% – on my laptop after it has just been booted (with networking disabled) up and only showing some idle terminal windows and a powertop. I realize some of the residency loss could be due to having to drive a display, but yeah, the following screenshots is what I see on the laptop (2nd screenshot with VMB1USB which has the bInterval = 2 connected):
(as I mentioned earlier my N100 cannot use pc10 due to the PCIe SFP+ card, but similar observations stand there, just with it having same residency in pc8.)
I guess it is time for me to boot up a live usb of debian (on the laptop, cause I don’t have monitor or keyboard/mouse for my N100…)
EDIT: I see exactly the same behaviour on Debian 12.9 as I see on NixOS (couldn’t find 12.6 to download.)
EDIT 2: Oh well, not sure which one of the things I did over past multiple days made this better, but I reverted back to the original kernel without the bInterval patch and my N100 just chugs along now without a care in the world. And this is why, my friends, we should keep a work log T_T
(My laptop still suffers though)
Thanks a lot for sticking around with me for this one Andy, lots of best wishes to you.