How laptop makers implement the power button over USB-C?  - Page 1
Forum section: electronics / projects

author: Warhawk
author_rank: Frequent Contributor
timestamp: July 02, 2020, 02:26:37 pm
content: Guys, I am not a big fan of USB-C. Nevertheless, I have two laptops with USB-C that I use with the docking station and external screens. I do not need the internal screen when docked and for this reason, I like to keep the lid closed. This allows me to place the laptop of the table and have more working area on my desk. I can theoretically wake up or enable the laptop using the button found on the docking station. Unfortunately each manufacturer (HP, Lenovo, Dell) uses a different implementation for the wake-up functionality. Only the same-brand docking station enables the laptop. (HP dock enables only HPs, Lenovo dock only Thinkpads, etc.).Does anyone know how laptop makers implement this feature? I assume that it is either a sequence, specific voltage, or the combination of both, on data signals. I am hoping that I can maybe create a small board that one puts between the dock and the laptop that enables all based on the config.Believe or not, I am not the only one who has this problem. I've already met couple people looking for same.Thanks for any tips.

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: July 02, 2020, 10:30:42 pm
content: Many computers wake on key press (either any key or a specific "power button" key on some keyboards) or even mouse button click, so a device that emulates a HID might work. Easy to test out, too, with just a keyboard connected to the powered USB port as blueskull mentioned.

author: Warhawk
author_rank: Frequent Contributor
timestamp: July 03, 2020, 03:53:22 pm
content: Thanks guys but this requires the computer in sleep. Wake over USB does not enable the laptop when disabled.

author: Jeroen3
author_rank: Super Contributor
timestamp: July 03, 2020, 04:31:55 pm
content: No, wake over usb by keyboard can work in S5. Same as wake on lan.

author: Warhawk
author_rank: Frequent Contributor
timestamp: July 05, 2020, 01:16:29 pm
content: Quote from: Jeroen3 on July 03, 2020, 04:31:55 pmSo any tip how to make a USB device that powers up the laptop when disabled? Because I am seriously doubting this is possible for laptops. There might be some desktop PC motherboards with this functionality but this is not the case of laptops. Otherwise, why would Lenovo, HP and Dell used different approach?

author: ejeffrey
author_rank: Super Contributor
timestamp: July 05, 2020, 07:02:38 pm
content: Quote from: Warhawk on July 05, 2020, 01:16:29 pmHow do you know they aren't? Just because they are incompatible doesn't mean they aren't all using wake on USB. They may just implement different virtual keycode or only respond to a matching USB vendor/product ID. There might be another thunderbolt based way to do wakeup too but I don't see any reason to think it can't be standard wake on USB.

author: ConKbot
author_rank: Super Contributor
timestamp: July 05, 2020, 11:59:01 pm
content: It's a shame that manufacturers ditched regular dock connectors for USB-C, at least on workstation laptops. Got one for my work PC. But it only supports one monitor at mediocre resolution, so DP and HDMI on the laptop itself were still needed. Ethernet is presumably a USB to ethernet adapter, so corporate policy doesn't allow that without more waivers than I can be bothered with. The USB hub works, but I only have a keyboard and mouse that needs to be plugged in regularly, already plugged into the monitor hub. USB PD works, but 65-100W isn't enough for a workstation laptop. So in the end, it's a $200 power button.That being said, I agree on the assessment that it's most likely USB shenanigans + vendor lock in of some sort. A USB-C pass-through card that breaks out signals for you to sniff and decode D+/D- and the CC pins would be where I'd start looking if you can't find anything online information.

author: Jeroen3
author_rank: Super Contributor
timestamp: July 06, 2020, 05:35:25 am
content: Quote from: Warhawk on July 05, 2020, 01:16:29 pmYou just set "wake by keyboard" enabled in the uefi and a standard keyboard wakes up the laptop?