Just to be sure, I also went through all the tasks in Task Scheduler, trying to figure out if a scheduled action was the culprit. Powercfg /waketimers (which needs to run in an elevated command prompt) said there were no active wake timers on my system, so nothing to do there: Powercfg /lastwake didn’t give me any new information, it also said that it was the NIC waking up the computer: Some time later I came back to the issue and this time my research first led me to the powercfg utility. After a while, I resigned myself and didn’t even try to put my computer to sleep before bed. ![]() I don’t remember what else I did to try and fix this, but if there was anything else, it didn’t work. Maybe it’s supposed to say “disabled” instead of “disconnected”, and it lets the NIC go to sleep if WoWLAN is disabled… So I didn’t really mess around with this one. I think of WoWLAN as an event, not a persistent connection. The documentation says “Sleep on WoWLAN Disconnect is the ability to put the device to sleep/drop connection when WoWLAN is disconnected.” but I don’t understand what “WoWLAN is disconnected” means. The documentation for GTK rekeying for WoWLAN is not clear on what it does, but some additional research shows that it’s related to the PMWiFiRekeyOffload standard keyword for power management, which says “A value that describes whether the device should be enabled to offload group temporal key (GTK) rekeying for wake-on-wireless-LAN (WOL) when the computer enters a sleep state.” So just like the previous two, we want that enabled.įinally, I just can’t wrap my head around what Sleep on WoWLAN disconnect is. They are enabled by default, and it sounds like that’s the way it should be. The first two let the OS “delegate” some work to the NIC when it is sleeping, so that some things can happen without it waking up. For obvious reasons, of particular interest were NS offloading for WoWLAN, ARP offloading for WoWLAN, GTK rekeying for WoWLAN, and Sleep on WoWLAN disconnect. Intel provides some documentation on those that was pretty useful. Playing around with the other settings in Device Manager didn’t help. But that setting is needed for WoWLAN to work, so I started looking for a solution. It was clear that the NIC was responsible for waking up the computer, and sure enough, if I disabled its “Allow this device to wake up the computer” setting in Device Manager, the problem went away. ![]() I first went to Windows’ Event Viewer and found this sequence of events (the first one has the wrong time because Windows still thinks it’s the same moment as when the computer went to sleep, and the second event fixes that by syncing the OS clock with the hardware clock): Things were great until I noticed that my computer was waking up on its own every night after I went to bed and put it to sleep. ![]() In my case, the only relevant setting (and maybe not even that, since I only use WoWLAN with state S3 (sleep), not S4 (hibernate) nor S5 (soft-off)) was S4/S5 Wake on LAN.įor the second step I went to Device Manager, double-clicked my wireless card under “Network Adapters”, and made sure that Wake on Magic Packet and Wake on Pattern Match were set to Enabled in the Advanced Settings tab and that “Allow this device to wake up the computer” and “Only allow a magic packet to wake up the computer” were checked in the Power Management tab.Īnd voilà! I was immediately able to put my computer to sleep, and wake it up with a Wake-on-LAN packet sent through the WiFi. Some people might not be able to complete this if their motherboard/NIC/BIOS doesn’t support WoWLAN, and in that case there’s not much to be done other than changing hardware (or making sure it’s not just a missing BIOS update, which it probably isn’t). The first step was about looking for the appropriate settings in my BIOS, and setting them to the correct values. Configure the wireless NIC settings in Windows.Getting WoWLAN to work wasn’t particularly hard, it basically boiled down to two things: For several months now I’ve been struggling with an issue that showed up after I managed to set up Wake on Wireless LAN (WoWLAN) on my desktop computer, and I thought the whole process it would make for a great blog post, so here we go! Chapter 1: got it to work!
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