Solved PC has started waking up when TV turns on

My PC has started waking up from sleep when my LG CX (WebOS) TV is turned on, which is wired to the PC. This is new behaviour. Previously the TV could be turned on without waking up the PC. No new hardware has been attached to the PC.

If I unplug the TV from the PC and turn on the TV the PC still turns on.

powercfg /lastwake produces:

Instance Path: PCI\VEN_10EC&DEV_8168&SUBSYS_E0001458&REV_16\4&372df7c7&0&00E0
Friendly Name: Realtek Gaming GbE Family Controller
Description: Realtek Gaming GbE Family Controller
Manufacturer: Realtek

If I understand correctly this is the network interface controller (NIC), indicating a wake on LAN (WOL) event. I can't turn off WOL completely because I need it to be able to wake the PC to stream games over the Steam app.

Again, this is new behaviour and no new hardware has been attached to the PC.

Silly question - do you have a sensitive mouse attached to pc?

When laptop is sleeping, moving the mouse will turn on laptop again. It takes the slightest vibration of my mouse to turn my laptop on.
TVs can be quite "noisy" starting up and that may be enough.

I have to close lid to avoid this.

Easy to test - remove mouse before you put pc to sleep.

I accept this is probably "clutching at straws" but you never know.....

cereberus said:

Silly question - do you have a sensitive mouse attached to pc?

Click to expand...

I disabled my mouse waking the PC some time ago, so I could move it aside when the PC is sleeping. There's probably a guide on this site, but here's how to fix your issue. Just press a key on the keyboard to wake your laptop afterwards. Not the space bar, as that can cause apps to launch and other unexpected results.
Also, the TV is wall-mounted. Good idea though.

moonkey said:

I disabled my mouse waking the PC some time ago, so I could move it aside when the PC is sleeping. There's probably a guide on this site, but here's how to fix your issue. Just press a key on the keyboard to wake your laptop afterwards. Not the space bar, as that can cause apps to launch and other unexpected results.
Also, the TV is wall-mounted. Good idea though.

Click to expand...

No need to sort my issue - sorted long ago - I now use cordless mouse, and just put it aside when not in use.

@moonkey
If your LG TV is connected to the PC via HDMI, then it may be HDMI-CEC that is turning on the PC.

Go into your TV Settings and try to disable CEC for the PC. That may not be possible, so you may need to disable CEC for all devices which wont help if you have an AV Receiver.

has you're tv been linked to pc with bluetooth.

Unplugging the TV from the PC has no effect, the PC still turns on when the TV is turned on. Disabling CEC similarly had no effect.

The PC does share Bluetooth speakers with the TV that cycle when the TV is turned on, but I removed the Bluetooth dongle from the PC (it doesn't have native Bluetooth) and the PC still turns on when the TV is turned on.

I think the router may be transmitting a signal throughout the LAN when the TV is turned on, as
powercfg -lastwake points at the NIC.

@moonkey
Since you have exhausted all of the other possibilities, go into the TV Settings -> Network and see if you can control WOL. LG may not name it WOL, so look for an option you may not recognise and try that.

The only other option would be to go into your router settings and try to isolate the TV from the PC, maybe putting the TV on a different subnet would work?

trumpy81 said:

Since you have exhausted all of the other possibilities, go into the TV Settings

Click to expand...

Great idea, but I have a question. Since it's his PC waking up wouldn't he need to turn off wake on lan(magic packet) for whichever network adapter he's using on the PC rather than in his TV settings? Now if there's a setting in his TV that prevents it from sending a magic packet, that would be a horse of a different color.
I'm not sure. That's why I'm asking.

Checked the TV. It has no WOL controls.

It's definitely the NIC waking up the PC:
- with the Ethernet cable disconnected the PC doesn't wake when the TV is turned on
- with the Ethernet cable connected the PC does wake up when the TV is turned on
- weirdly, if the Ethernet cable is disconnected and I plug it in, the PC turns on even if the TV is off.

It seems the TV is prompting something on the LAN that also happens when connecting the Ethernet cable to the PC.

@glasskuter
He indicated that he uses WOL to wake the PC for gaming/streaming, so he cannot disable WOL on the PC.

The only other option would be to do that in the TV.

Whether or not the TV has such a setting is another question altogether ... lol

I just returned a Beelink Mini connected to my TV because it wouldn't awake once it got to sleep. I'm kinda jealous of you.

Curious about something else. For testing only..... Does your PC have a wireless adapter? If so, disconnect ethernet cable and connect wirelessly. Let the computer sleep. Does turning on TV wake the computer? if so what does powercfg /lastwake say?
Also can you open command prompt as admin and typepowercfg -a Post a screenshot

Does the LG webOS have an option that will prevent the TV from sending WOL packets? If not, see if you can add a rule in your router's firewall to block the TV's outgoing UDP broadcasts that are targeted at port 12287.

Is the TV connected by wifi or ethernet cable? Generally TV functions are to turn on TV, not visa versa


A Guy

A Guy said:

Generally TV functions are to turn on TV, not visa versa

Click to expand...

On a Google TV it is possible to send WOL magic packets to any device that's on the same subnet as the TV (as long as you know the device's MAC ID).

SOLVED

Given that we're almost 20 messages deep, here's a recap:

Suddenly, the PC has started waking up from sleep whenever the TV is turned on. Testing has confirmed that it is the NIC which wakes the PC. Weirdly, even though turning on the TV always wakes up the PC, when the Ethernet cable is disconnected, the PC is sleeping and the TV is off, the PC wakes up as soon as the Ethernet cable is inserted. So though turning on the TV wakes up the PC, apparently other things go bump on the LAN as well. To note, my NUC does not wake up from sleep when the TV is turned on. Both the PC and the NUC run auto-updated Windows 11 Pro.

The PC has a Gigabyte B360M H motherboard with firmware F15b
- It only has Ethernet. The NIC is a Realtek Gaming GbE Family Controller
- The NIC driver was updated from Microsoft 1.0.0.14 to Realtek 1168.16.1123.2023
The TV is an LG OLED 55CX6LA TV with WebOS 04.50.53
The router is a Sagemcom Box 12 (SagemcomF@ST5359 KPN) with firmware V12.C.23.04.39
Neither the PC (BIOS), the TV nor the router have WOL controls.

The solution was to enable the option to "Only allow a magic packet to wake up the computer" in Device Manager\Realtek Gaming GbE Family Controller\Properties\Power Management.

Note that I updated the generic Microsoft NIC driver to the latest Realtek one. The generic Microsoft driver may have this option too, I am not sure I checked. Whatever the case, even after updating the driver the issue persisted until I enabled filtering for magic packets.

What the underlying issue is, and why it suddenly started, I don't know. I have recently added a mesh extender to my wireless network, perhaps it is bouncing packets around the LAN.

Thanks for thinking along with me. I appreciate it.

Thanks for letting us know the solution

I would not have thought the solution was with your PC, but you get that. I'm glad you got it sorted!

After reading your solution, I went and checked my 2 Ethernet NIC's, one Intel I211 (my main NIC), and one Realtek PCIe 2.5GbE Family Controller. The Intel NIC does not have any options to control WOL, that I can find anyway.

The Realtek NIC on the other hand, does have an option to Wake on Magic Packet or Wake on pattern. Unfortunately, I don't have a 2.5GbE router or switch, so I can't really use the Realtek NIC, I could use it with 1GB, but that just seems like a waste.

I also checked the Intel Wi-Fi 6 AX200 Wireless NIC and it has Wake on Magic Packet or Wake on pattern as well.

So if I wanted to use WOL on this machine, I would have to use Wi-Fi or the Realtek NIC, go figure ... lol

It may be worth checking if the latest driver from Intel for your main NIC has the options. My Realtek NIC ran on Microsoft's generic driver out of the box. Good luck.

I did install the latest Intel drivers, but no go, the options did not change.