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Later in the conversation someone links to a Twitter exchange which I found quite interesting: > (@m_ou_se) I just tried to charge my phone by connecting it to
by bradrn 4y ago
Later in the conversation someone links to a Twitter exchange which I found quite interesting:
> (@m_ou_se) I just tried to charge my phone by connecting it to my laptop (with USB-C), but instead of my phone, my laptop started getting charged, quickly draining my phone's battery. Uh, what.
> (@Gankra_) in case you aren't familiar: there was a semantic function of asymmetric usb cables that symmetric usb-C has broken. to "fix" this, each device picks a number for how subby it is, and the less subby one is the dom and charges the sub. these numbers can be surprising.
> (@m_ou_se) After some experimenting, I concluded that Dell laptops are the most powerful USB-C PD doms followed by ThinkPads, while phones and MacBooks are (equally) subby. Connecting phones and MacBooks with each other results in a switch fight.
(https://twitter.com/m_ou_se/status/1502664680602492933 https://twitter.com/m_ou_se/status/1502664680602492933)
- detrites 4y agoI can't fathom how we all went ten years without knowing this stuff.
- doubled112 4y agoDidn't have a laptop with USB-C ports until 2021. I've got a couple now. One does PD, one does not. One does video out, one does not. One charges fast, and you guessed it, one does not. Is it supposed to be easy because the cables fit? Honestly, it's only made it harder and I know what I'm doing. "It fits but doesn't do what I was told it would" is probably more confusing to the average Joe.
- philliphaydon 4y agoBut but everything used usb-c so iPhones must be usb-c now toooooo!!! I like the physical connection of usb-c but that’s it. The whole thing is an absolute mess. I’m going to miss lightening port.
- mycall 4y ago> everything used usb-c so iPhones must be usb-c now toooooo EU agrees with this.
- WirelessGigabit 4y agoNo you're not. Even the worst USB-C cable is better than lightning. An iPhone doesn't charge another device. So you're good. Also, then hopefully I won't need to switch out cables every so often because of a shorting pin #4.
- tinus_hn 4y agoIf you plug in a semi recent Samsung phone to a USB-c monitor, not only will it charge, but you will also get some kind of desktop experience on the monitor.
- xg15 4y agoBut wasn't there supposed to be a way to change the roles afterwards, according to user input? It would be super useful at times to charge one laptop (or phone) off the other - provided I have some way to specify which one should be charged.
- xattt 4y agoThe most appropriate and most sexual way would be to have a safe word.
- CoastalCoder 4y agoAt this point, it might make more sense to just put a condom over all male USB connectors.
- xg15 4y agoStill wondering if technically the host would be the dom since it gets all the control or if the device would be the dom since it gets all the power.
- plasticchris 4y agoI have USB c to c cable that will charge in one direction. It’s not labeled, so I put some arrows on it :)
- trompetenaccoun 4y agoThis thread is getting more and more interesting.
- AndrewOMartin 4y agoThe fact that this is such a rare comment is damning.
- walthamstow 4y agoI thought whichever one is plugged in second is the one that receives the charge, but it may be vice versa. Either way, it's the order of plugging that matters.
- Traubenfuchs 4y agoIs there like a C function, dll or device manager property I can check to find out how subby or dom my device is or is this only possible via comparison?
- smith7018 4y agoMy M1 Max MacBook Pro treats my Galaxy Tab A8 like an external battery which makes development quite annoying. It's strange that this hasn't been figured out in 10 years.
- sofixa 4y agoOn Android you can configure that (usually there's a popup after plugging in, if not it should be in the power settings) on multiple levels - if it should charge, if OTG charging (the phone/tablet providing power) is enabled, etc.
- martinald 4y agoIf you've set this and it doesn't work properly still, try swapping out the cable. A bad quality USBC cable would always make my phone (occasionally) charge my MacBook but not the other way around, for some unknown reason. Drove me crazy until I changed the cable.
- mkl 4y agoThis metaphor seems backwards. Wouldn't the sub give its power to the dom?
- Pelic4n 4y agoNever heard of a power bottom?
- dymk 4y agoTypically no, unless it’s a power bottom.
- willcipriano 4y agohttps://m.youtube.com/watch?v=Uc9_mxvP1K0 https://m.youtube.com/watch?v=Uc9_mxvP1K0
- fuzzylightbulb 4y agoNow dymk, I heard speed has something to do with it.
- dymk 4y agoSpeed has everything to do with it (although the cable must be rated for fast charging)
- hammock 4y agoHow one interprets this question is like a personality test
- karmakaze 4y ago> phones and MacBooks are (equally) subby. Do you mean phones here or iPhones? I've been charging my LG phones (G6 & G8) from MacBook Pros for years and never noticed an unexpected switch.
- madeofpalk 4y agoAs you're touching on, it doesn't make sense to make a blanket statement for all phones. Also, iPhone is not USB-C, so I guess it doesn't participate in this negotiation.
- wongarsu 4y agoWhat about Lightning to USB-C cables? I assume the device is talking the USB protocol at that point? Or does that connection only allow charging in one direction?
- mathieuh 4y agoI've charged my iPhone off my MBP using a lightning->usb-c cable and I didn't notice anything weird. I've also been able to charge my iPhone off my iPad using the same cable so maybe it is one way.
- dfox 4y agoThat particular cable only works in one direction. Lightning itself can power external devices, but the whole mechanism is completely different than how USB PD over USB-C works (it is designed for low power peripherals and thus can output unregulated 3-ish V in order to save on DC/DC conversion losses, similar capability of devices powered entirely from V_CONN is quite recent and hackish addition to USB-C).
- karmakaze 4y agoI forget that other interface still exists. Is it only iPhone and keyboard/touchpad/mouse/pencil now?
- misnome 4y agoThis is more interesting than the linked poll, thanks.