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I heard some rumors that none of the USB wireless adapters can support Wake on Wireless LAN because USB can't maintain the adapter's power when in sleep mode. Is that true?

I don't know why but every time I sleep my computer, the USB ports still have power and I can charge my phone. How could it be impossible for a USB wireless adapter to support WoWLAN?

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closed as unclear what you're asking by Ƭᴇcʜιᴇ007, Moses, Tog, Carl B, mpy Nov 18 '13 at 12:18

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question.If this question can be reworded to fit the rules in the help center, please edit the question.

    
So where exactly did you hear these 'rumors'? Can you cite something that states this? Otherwise, this is just unanswerable speculation (IMO). When you tried to get it working, what were your results? Where are you getting stuck while implementing it? –  Ƭᴇcʜιᴇ007 Nov 14 '13 at 18:08
    
What you describe is device specific. Wake on Wireless Lan must be added to the device specifications. Likewise your ability to charge your phone while your laptop is sleeping was actually built into specifications of the laptop. –  Ramhound Nov 14 '13 at 18:14

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up vote 4 down vote accepted

The decision of whether or not to leave the USB port's power circuit enabled when the system is in ACPI S3 ("Sleep" / "Suspend to RAM") is left up to the motherboard BIOS/firmware. It may even have a BIOS option you can configure for this purpose, to enable/disable the USB power when the system is asleep or even turned off.

However, there aren't any motherboard implementations, that I know of, that will keep the data part of the USB connection enabled while in S3 or powered off. When the CPU is suspended or off, it doesn't make sense to maintain the data link layer of the USB bus, because even if you sent a message through the bus, the CPU wouldn't be there on the other side to receive the message. But the CPU doesn't have to be on for a normal ethernet card to do Wake on LAN, either, so I did a bit of research into this....

USB controllers are usually connected to the CPU using something like PCI or PCI Express. PCI and PCI-E support Power Management Events, which are essentially what is used by an on-motherboard NIC to tell the system that it's being woken up due to a WOL. In theory, if the USB controller were receiving standby power from the PCI(-E) bus, it could then decode a wake on LAN magic packet from a USB device, and translate that into a PCI(-E) PME, which would trigger the wake. So I believe that it is possible, in theory, at a hardware / system design level, to implement a motherboard and a USB Ethernet or WiFi chipset that would support this.

I just don't know of any that do, off the top of my head.

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Thanks, you did make it clear. –  demonguy Nov 15 '13 at 4:33
    
But i'd like to go into details about it. So what exactly "something like PCI or PCI Express" is? Could give a document url or something else?Actually, since usb mouse can wake the computer, i do think it's possible for a wireless adapter to do so –  demonguy Nov 15 '13 at 4:39
    
Yeah, but how would it happen? How would you direct a packet to a non associated wireless adapter? On wired you just broadcast the WoL for the MAC address, since it actually is connected to the ethernet switch it gets it. On wireless though, the layer2 is way different. –  gnp Sep 12 '14 at 22:00

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