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Explaining 4K 60Hz Video Through USB-C Hub

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Re: Explaining 4K 60Hz Video Through USB-C Hub

#131

Post by rhinoceraptor »

MaddAgent wrote: post #109
ben-schaaf wrote: post #87

Earlier quoted context omitted.

On the topic of power, I really don't understand how USB-C is supposed to replace charging cables. USB-C is limited to 100W. That's enough for a switch, phone or low power laptop, but if this[0] is anything to go by the 6 core intel laptop CPUs already eats 80W of power. Add an extra 2 cores and you might not even be able to sustain a CPU load without draining the battery. Not to mention much higher power draw GPUs.…

So you're thinking the new MacBook Pro 16 with an 8 Core CPU and a GPU using the included 96Watt USB-C charger may drain the battery under full load?

It will drain the battery at full load, the i9 is a 45 watt TDP and the RX 5500M is 85 watt TDP (plus display, ram, disk, etc).

However, there's no way the cooling on the laptop can support that much power draw, so I'd expect it to throttle itself way before you'd drain the battery while plugged in.

Re: Explaining 4K 60Hz Video Through USB-C Hub

#132

Post by izacus »

tlamponi wrote: post #70
Nextgrid wrote: post #69

Earlier quoted context omitted.

That world will not happen unless every single device including entry level phones and size-constrained devices somehow magically include all the circuitry required to handle all the different alternate modes. Also, as far as I understand there just isn’t enough pins to support all the modes at once so trade offs have to be made...

I can plug in a X1 carbon thinkpad in my monitor (some ultrawide dell) with USB-C support just fine. I then get video, audio, USB (the monitor has a hub where I have mouse and keyboard connected) _and_ charging/powering my laptop over a single link. Works today with Linux here! It's just magical, I tell you. The world started to happen already, it may not become all that good and 100% universal soon or anytime, but g…

And if you plug a Samsung Galaxy S9/10/Note into that same USB-C, a full desktop will appear on your monitor as well using your existing ethernet, mouse, keyboard and audio outputs. Something not possible with full sized HDMI ports.

Re: Explaining 4K 60Hz Video Through USB-C Hub

#133

Post by chx »

bloopernova wrote: post #96
cesarb wrote: post #90

Earlier quoted context omitted.

USB4 is more than just "renamed Thunderbolt 3". It adds USB 3.x tunneling while Thunderbolt 3 could only tunnel PCIe and DisplayPort (AFAIK, it faked USB 3.x tunneling by having a PCIe USB 3.x host on the device).

so USB4/neo-Thunderbolt is going to be the true universal connector? Does it still have a "mess" of different levels or protocols? I'm hoping the thunderbolt 3 devices I have will "just work" with usb4 ports.

> Does it still have a "mess" of different levels or protocols?

of course

Re: Explaining 4K 60Hz Video Through USB-C Hub

#134

Post by whoopdedo »

yaantc wrote: post #33
fulafel wrote: post #10

re "Driver availability and compatibility for Mac/Linux is spotty to non-existent": Is it true that DisplayLink doesn't work well with Linux? Some years ago people were saying that the usb-to-monitor dongles worked well. A casual web search also gives this impression, with good support provided by the DisplayLink company.

You can make Display Link (DL) work with Linux, there are drivers from the vendor and an adaptation script for Debian based distros [1] (and variants for others IIRC). You may have to fiddle with the configuration to avoid issues like minor display corruptions or cursor glitches. I made it work clean once, but in the end I returned the dock. DL is to me a bad idea, except is some specific cases. The way DL works is t…

I was curious about that compression and found an analysis[1] of the DL protocol. The first thing I saw was that it doesn't just render to a framebuffer on the PC, it renders twice, once at 16bpp and another at 8bpp (which it will combine to achieve 24bpp). The use of Huffman encoding seems consistent with the state of compression in 2003 [2]. If doing it today you'd probably go with x264 lossless but that would have been too slow 15 years ago. In conclusion I'd guess the lag is caused by the split framebuffers. Or an inefficient proprietary driver.

[1] https://pdfs.semanticscholar.org/a3ed/739f229315fe8673f227e7...

[2] https://forum.doom9.org/showthread.php?t=165545

Re: Explaining 4K 60Hz Video Through USB-C Hub

#135

Post by izacus »

Derbasti wrote: post #78

Let's talk power: The USB-C PD charger of my Nintendo Switch does not charge my phone, but it does charge my Surface. My phone's USB-C charger does charge the phone and Surface, but not the Switch. My USB-C battery pack charges my phone, but is charged by my Surface. Yeah, it just works. How do, say, a battery pack and a Surface negotiate who is charging who over a symmetric USB-C-to-C cable?

Nintendo Switch isn't standards compliant with USB-C and as such it's pretty much the same as having any other non-compatible proprietary standard.

Re: Explaining 4K 60Hz Video Through USB-C Hub

#136

Post by snagglegaggle »

Nextgrid wrote: post #26

The USB-C spec is an insane mess. The fact that every port used to be different is actually a feature, as it helps you identify which device supports what based on the ports it had. If you see an HDMI port on a laptop you can be sure it's going to output some kind of video signal over that. If you see Thunderbolt then you're sure the machine supports Thunderbolt. USB-C just jams all these incompatible standards into…

Due to their high bandwidth I think we should have standardized around display connectors. It actually looks like USB-C "gives up" and just pushes out DP on unused copper? So it's like some super high bandwdith negotiation layer that could just... not be there.

Or, it looks like thunderbolt would have been a good option. But it seems overengineered -- the transport layer doesn't need to know anything about the data.

Re: Explaining 4K 60Hz Video Through USB-C Hub

#137

Post by alias_neo »

mangosherbet wrote: post #117
alias_neo wrote: post #82

Earlier quoted context omitted.

I also recently bought a monitor with USB-C (Thunderbolt 3) which I can plug it's single cable into my DELL XPS and charge it, output 4K@60 to the display, and have my mouse and keyboard which are connected to the back of the monitor. The downside is when I want to use the same kb/mouse with my desktop, I have to unplug them from the monitor and plug them into the desktop.

Which monitor did you buy? I've been looking for one with USB-C support as I also have an XPS13. I have a 9360 and I know it uses a neutered TB3 PCIe lane (or something of that nature) so I'm concerned about being able to use a 4k 60 fps display with it. Have you had any issues? I use both Ubuntu and Windows on the machine, have you tried both with the monitor?

I bought the LG 27UL850, I have a 2019 XPS 13.

I don't run Windows so I can't answer that but Ubuntu 19.04 runs fine, although I've had minor issues with the laptop coming out of sleep and not outputting to the display occasionally.

EDIT: It's really nice in portrait for coding. I don't use the supplied stand but a desk mounted arm.

Re: Explaining 4K 60Hz Video Through USB-C Hub

#138

Post by alias_neo »

hkjhreiou wrote: post #95
alias_neo wrote: post #82

Earlier quoted context omitted.

I also recently bought a monitor with USB-C (Thunderbolt 3) which I can plug it's single cable into my DELL XPS and charge it, output 4K@60 to the display, and have my mouse and keyboard which are connected to the back of the monitor. The downside is when I want to use the same kb/mouse with my desktop, I have to unplug them from the monitor and plug them into the desktop.

> The downside is when I want to use the same kb/mouse with my desktop, I have to unplug them from the monitor and plug them into the desktop. I use a cheap USB hub which has a button that can switch between two outputs for this: https://www.amazon.co.uk/dp/B01MXXQKGM/

Thats a great idea thanks. It's a shame the monitor didn't integrate this for when I switch display input, I was hoping to reduce the number of cables and boxes I use :(

Re: Explaining 4K 60Hz Video Through USB-C Hub

#139

Post by crooked-v »

Eric_WVGG wrote: post #16

I saw this headline and was briefly excited for a moment that a USB-C hub finally existed. That is, a device like an ethernet hub or a USB hub, that would turn one port into several other ports of the same kind. This is an article about USB-C port replicators. Four years into this and not a real single USB-C hub exists. I’ve never seen such a botched rollout.

I have to wonder if the USB4 rollout will be any less awful.

Re: Explaining 4K 60Hz Video Through USB-C Hub

#140

Post by jjoonathan »

silon42 wrote: post #122
jjoonathan wrote: post #100

Earlier quoted context omitted.

It could be a long time. Bluetooth has been around for a good while and still has tons of "growing pains."

Bluetooth used to be mostly optional, now that some people (not me) are forced to use it for audio, things might get better in years/decade.

I'll drink to that!
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