Linux Developers Ponder Decade-Old Decision To Disable PCI Runtime Power Management By Default

[phoronix]

Phoronix: Linux Developers Ponder Decade-Old Decision To Disable PCI Runtime Power Management By Default

Back in 2010 was a change to disable run-time power management of PCI devices by default and leaving it up to user-space to in turn override it if desired. Now as we gear up for 2021, some upstream kernel developers are wondering about that original decision and possibly changing the default behavior to yield better out-of-the-box power savings with modern systems...

http://www.phoronix.com/scan.php?page=news_item&px=Linux-2020-PCI-PM-RT-Disabled

[piorunz]

I'm not sure if my motherboard has any PCI ports anymore 🤔😅 It's all PCIe nowadays.

[ms178]

Decade old decisions which hurt the user experience today... ouch. Someone should look over these regularly and re-consider if they make sense today.

[fransdb]

If they change this, then let them look at the age of the system. I still use systems which are around 10 years or a little older. Why? They do what they should do perfectly and there is no need for faster systems. If I would run games, then it might be a good idea to replace these machines, but I don't play games. Development, office use and servers, that's what I use them for.

All to often I see in these discussions that many people expect that users have cutting edge machines and that older systems are irrelevant nowadays. Why waste resources if they are still up to their task? Only last year I retired an aging 32-bit machine, not because it was lacking processor power, but only because I could not expand installed memory anymore past it's physical 750MB limit. But "newer" systems with max. 16-32GB are still quite capable to serve everyday tasks as indicated above, at least in a SOHO environment.

[blackshard]

I'm not sure if my motherboard has any PCI ports anymore 🤔😅 It's all PCIe nowadays.

Even if you don't have any exposed PCI bus, the PCI bus still exists and may connect various integrated devices and chips. PCIe is also an evolution of PCI, but still shares part of the protocol. lspci will tell you all the PCI/PCIe devices of your system.
I think the 16-bit ISA bus is still present in this form nowadays.

[blackshard]

Decade old decisions which hurt the user experience today... ouch. Someone should look over these regularly and re-consider if they make sense today.

IMHO the big problem is the all-or-nothing logic, while instead there should be some form of blacklisting/whitelisting due to the huge hardware variety.

[FireBurn]

Powertop is useful for figuring this out. It allows you to enable PM for each device to see if it has issues. I had an issue with a mouse that would switch of the Lazer after 1 second of not being used until a button was clicked - making it useless

[oleid]

Ah, good old Chesterton's Fence. Hope they analyze it properly.

[elatllat]

I recall a wifi chip the would sleep when I wanted to use it. As long as userspace can change the default it's all good.

[jeisom]

This seems like something that should be enabled by the init system with a allowlist.