Have the WiFi module wake the system from suspend

Implement a mode with the WiFi modem enabled during suspend and have the modem wake the system on link changes.

use-cases#75

changed the description

I think this is Wake-on-WLAN (WoWLAN) https://wireless.wiki.kernel.org/en/users/documentation/wowlan

• Do we have the hardware in place? our Wifi module supports wowlan and we have the wakeup source wired up? any reference / link to a source?
• If so, do a first test using iw when connected to an AP, with a laptop waking up the devkit (magic frame / ping)
• Test using iw to configure wakeup on "link changes", as suggested above.
• (new issue): find WoWLAN "Patterns" we want to have in order for the essential services to wake up the system on incoming messages (calls via xmpp/matrix, messaging via xmpp/matrix, IMAPS email). best-case would be to stay independent of the TCP-port, but for testing, it could be a start.

mentioned in issue developer.puri.sm#100

added important label

added suspend label

changed title from Have the WiFi modem wake the system from suspend to Have the WiFi module wake the system from suspend

suspending redpine feels more like unloading / shutting down. I get a new "iw dev" phy number after resume, it takes seconds to connect again, wowlan is disabled after resume and so on.

How's the firmware's view of WoWLAN currently?

there's another issue for WoWLAN actually: https://source.puri.sm/Librem5/linux-next/issues/100

Removing importantsince we don't suspend atm, agreed?

removed important label

why would we want to wake the system on "link changes"? I think we can even close this issue for the same reason as https://source.puri.sm/Librem5/linux-next/-/issues/100#note_184816

in short: we don't have plans (due to missing hardware support) for user-defined wakeups based on tcp/ip patterns - be it for the baseband or wifi modem. Instead we'll most likely work on resuming periodically (until an internet connection is established) and suspend again.

This is for the case where we would keep the Wifi card powered during suspend.

It should wake on link changes and any packet so I think this is different from the WOW case

what is the value in having wifi wake up the system on "link changes" or "any packet"?

I still don't see the goal of this issue really. In my mind, we can only wake the system ourselves using an rtc. wifi seems to be reconnecting reliably in that case. but that's not at all what this issue is about. @angus.ainslie ?

mentioned in issue OS-issues#237

mentioned in issue OS-issues#302