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Comment by yjftsjthsd-h | Hacker News Reader

Looks nice, uses coreboot and disables ME :), i5/i7, "Up to 40 GB DDR4", "2× M.2 SSD. Up to 4TB total." Holy cow that's a powerful machine.

> USB Type-C Power Delivery Compatible

It's capable of charging by USB-C? Then why does it have the old-style circular power jack?

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Just a guess, but charging by the old school barrel jacks requires next to no protocol support. You just need to provide the correct voltage, and supply enough current.

Whereas with USB-C, you need to speak USB-C before it'll charge.

EDIT: oh, and it gives you the ability to avoid potential security attack vectors.

I’ve wondered this with systems like my work-provided HP Elitebook as well. Best I can think of is that some customers may require the ability to charge a laptop via a port that doesn’t also double as a data port?

Given some of the crazy hardware security attacks we’ve seen over the years, I’m a lot more paranoid about plugging in a rando USB-C cable than plugging in a barrel connector. That said, knowing to look for tip polarity, voltage, and available amperage is a lot to ask of people. I wish we had a standardized power-only charger option.

Because it only has a single usb-c port. They probably want people to have the option of charging the laptop while also plugging in something over usb-c. Why they didn't just do two usb-c ports, I don't know. Maybe someone from System 76 can answer that.

They don't make their own laptops (yet, it is in the plan but probably not for 10 years), they buy enough laptops to have input on how they are designed, but in the end they don't get everything they want.

Edit: 10 years is my guess. There are hints they might make their own laptops sooner. Time will tell.

You'll need to use the barrel charger for applying firmware updates. The Lemur Pro has additional circuitry to support changing the battery even if it completely drained.

Wait, ignoring firmware... you need to have some charge in order to charge with USB-C? Couldn't it use the lowest power modes until it has enough juice to communicate? This seems like a serious flaw with USB PD.

Go long enough and even your minimal charge is exhausted

Then how can Macs be charged if they are fully exhausted?

I have no idea. Maybe they can't, but we won't find out for 5 years when someone brings one out of a closet. Maybe there is enough current leakage when in non charging mode for them to run that much electronics.

This is inaccurate, the Lemur Pro supports charging through USB-C with a dead battery.

That seems to be an implementation flaw. USB-C provides 5V by default with no negotiation which should be enough to power the controller and allow it to negotiate a higher voltage.

> USB-C provides 5V by default with no negotiation

Just to be pedantic, USB-C does need negotiation before it provides 5V, but that negotiation is just a pair of resistors of a specific value.

(Since the USB-C cable is symmetric, this negotiation is necessary to decide which end will provide the power. One end has both resistors wired as a pull-down, and the other end has both resistors wired as a pull-up. The end with both resistors wired as a pull-up will initially provide the 5V power.)

I routinely run my chromebook out completely out of battery charge, and it never has any issue charging with USB-C.

Backup? Higher current option?

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