Quote from: _MT_ on May 13, 2021, 09:17:13
Well, if the display isn't powered from a grid and there is only one cable connecting the laptop with the display, where does the power come from? Laptop's battery? Instead of charging it at home while it's "docked," you'd be discharging it? That's why you need two ports. And that's why I think it makes more sense (in the general case) to have display powered from the grid and use it to charge your laptop over the same cable that is used to send video to the display.
My point was that USB is already there. As long as you can live with the 100 W limit.
It could draw power from the laptop's battery, since if it's a low-power display, similar to the ones
in laptops, it wouldn't be a huge impact on it. Of course, more likely the laptop would be plugged in and would just pass power from the AC adapter through the USB to the monitor. And, of course, with a desktop, that would certainly make more sense, since you wouldn't need, or be able to, power the desktop from the monitor. So my point is that either way, you need a cable between the computer and the display, and so it makes more sense, in the example situation I gave where you're using a portable touchscreen display to control the computer without having to be sitting at it, to
only have that one cable, and have it supplying video, USB, and power
from the computer, vs having two cables attached to it, one going to the computer and one plugged into an outlet. And again, with a low-power display, this absolutely should be possible within the 100W limit of USB (heck, 100W should be enough to power even an ~30" gaming display). But the bottom line is that it just doesn't make any sense to have two cables plugged into it going to different places, seriously limiting its portability, vs just one. That
would make sense if you're actually on the laptop and just using the other display as a second monitor, and maybe that's what you're thinking, but remember, I'm talking about an entirely different situation.