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Displayport: A Better Video Interface

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Re: Displayport: A Better Video Interface

#251

Post by jacquesm »

ComputerGuru wrote: post #192
bee_rider wrote: post #3

I just like the little retaining clips, and the satisfying little click you hear/feel when plugging them in.

It’s a problem when the x16 slot is the bottom-most and the orientation is such that the clicky thing you must depress is on the bottom side of the DP connector when plugged in, and your case has a ledge after the PCI slots so you cannot realistically depress the latch. Of course, no one would realistically encounter a case/GPU/cable combo like that. Right?

Hm, my sample for that situation clocks in at about 100% (n=1). Especially the first time I needed to unplug that cable I was thrown for a bit, I ended up taking the whole case off the floor and using a thin screwdriver to depress the release button from the exposed side, that did the trick.

Re: Displayport: A Better Video Interface

#252

Post by masklinn »

immibis wrote: post #237
masklinn wrote: post #19

Earlier quoted context omitted.

For laptops it's pretty clearly USB-C with DP alt mode, just way too convenient to use a display as a charging hub. Desktop CG manufacturers don't care and it doesn't really drive sales (NVidia has completely removed it, and AMD's tends to be pretty buggy, it's really just DP over a USB-C port) so you need conversion add-in cards (usually from your mobo manufacturer). Also display manufacturers, standard connectivity…

Many connectors in one. Is the video output the left port or the right one? How about the charging port?

Just make all ports fully capable?

Re: Displayport: A Better Video Interface

#253

Post by ThatPlayer »

nfriedly wrote: post #25

I'm annoyed nvidia for putting the current generation of HDMI on their recent GPUs, but leaving them with an outdated version of DisplayPort. For a long time, my advice to anyone was to always choose DisplayPort whenever it was an option. But now that has to have the caveat of "if you have a new high-end GPU and a fancy high refresh rate monitor, HDMI might actually be better for your situation"

Yeah I hate this too because I just want to have more video outputs. My Valve Index doesn't like to be hotswapped plugged in, requiring a reboot. With 1440p144hz monitors, I just barely cannot run 2 of them (2x14Gbit) over a single DP1.4 (26Gbit) using MST. Windows will automatically drop colour down to 4:2:2 if I try it.

Not that DP2.0 MST hubs exist yet afaik, but when they do I'd have to get a new GPU. Which I guess is Nvidia's goal.

Re: Displayport: A Better Video Interface

#254

Post by rbanffy »

I was very disappointed that HDMI transfers a constant bit-rate stream of pixels - VGA, but digital. I expected that, given most display devices can at least hold a full frame in-memory, that the stream could be limited to the parts of the image that changes, allowing higher frame rates when less than the full frame changes.

That, and generating a signal could be much simpler than bit-banging on a DAC.

Re: Displayport: A Better Video Interface

#255

Post by pxc »

baby_souffle wrote: post #218
pxc wrote: post #137

Earlier quoted context omitted.

The Level1Techs KVM switches are rebranded Startech switches with 'dumber' firmwares whose dumbness affords better compatibility with niche DisplayPort features. I have a bunch of them and I like them pretty well, but getting a bunch of computers all plugged in turns out to be a bit of a nightmare, especially when you need some long-ish cable runs or you are daisy-chaining devices (e.g., multiple KVM switches, adding…

> The Level1Techs KVM switches are rebranded Startech switches with 'dumber' firmwares whose dumbness affords better compatibility with niche DisplayPort features. Rextron [1] is the actual ODM. They don't do any direct to consumer sales, though. That's why L1 / Startech / other "brands" sell them on amazon and the like. Last I spoke with the L1 guy, they were still having some issues with the high speed USB-C switch…

Ah! Great info. Thanks :)

Re: Displayport: A Better Video Interface

#256

Post by Our_Benefactors »

xboxnolifes wrote: post #239
xxpor wrote: post #117

Earlier quoted context omitted.

I'm 90% sure it was, but it looks like they did a major UI update to the site so it's not triggering the "that was it!" lightbulb in my brain.

Alternatively, you may have been thinking about ConnectPro. I ordered a kvm from them around the same timeframe and it was delayed quite a bit from backorder. (Though, they also did a major UI change, so might not be able to tell either).

Two thumbs down for connect pro. I ordered their top of the line 4 computer, 2 monitor DisplayPort KVM and it took months to arrive. I could not cycle between inputs using the buttons. They were more like a suggestion to use that signal path; I would constantly need to power cycle the kvm, monitors, or both.

I ended up ditching it on eBay at a significant loss for a $30 usb switch and just switch monitor inputs manually. Far cheaper solution and way less fussy.

Re: Displayport: A Better Video Interface

#257

Post by Blackthorn »

NewJazz wrote: post #194
pdmccormick wrote: post #169

Earlier quoted context omitted.

I once purchased a FireWire multi-channel audio interface with the express intent of reverse engineering the protocol in order to add Linux support. I purchased a specialized PCI card that was intentionally non-standard (not OHCI 1394) but could snoop and capture traffic between a device and a host. I chipped away at deciphering a register map for awhile, but eventually better USB audio devices came along that had mo…

Do the USB devices have comparable round trip latency? That is where USB really hurts and where the Thunderbolt audio interfaces seem to fond their niche today. I'm looking forward to audio interfaces that can do USB4 wrapped PCIe, but for now I live with the latency on Linux.

RTL latency doesn't seem that bad on chips that are built for the purpose, like RME's. Just the off the shelf stuff might be less than ideal.

If anything I think a problem is there's just overall too much slop in the whole chain, including the operating system, motherboard, whatever else. It's a little ridiculous that a $50 guitar pedal can easily get better RTL numbers than a $1500 computer system.

Re: Displayport: A Better Video Interface

#258

Post by pavon »

seanalltogether wrote: post #157
tivert wrote: post #77

Are there any KVM switches that do Displayport well (i.e. where switching between inputs does not look like a display disconnect to the PC)? I'm still using HDMI because I like to share my home multi-monitor setup between my personal machine and my work laptop, and the KVM switches are able to fool the PCs into thinking the monitor are always connected. Years ago I tried a Displayport switch, but it could not -- I as…

Can you explain why this is beneficial? I have a mac laptop and pc desktop at home that i switch between depending on whatever I need to do. By triggering a disconnect, it means all my mac windows that are on the main monitor will zip back over to the laptop so they're still reachable if i need to access them with the trackpad and integrated keyboard. When I switch the kvm back to mac all those windows jump back to t…

Flaky drivers. KVM induced unresponsiveness is pretty much the only reason I ever have to hardboot my computers.

Also, even if the drivers are solid, they take longer to renegotiate with a monitor that was removed and plugged back in compared to one they think was always there, which matters if you switch back and forth frequently.

Lastly, sometimes the OS doesn't put things back they way they were when you plug a monitor back in. If you have a laptop which has a lower resolution display than the external monitor, you'll often return to find all the windows shrunk to fit the laptop display. Not an issue if you run everything full-screen, but annoying if you tile windows.

Re: Displayport: A Better Video Interface

#259

Post by kccqzy »

londons_explore wrote: post #64
pid-1 wrote: post #48

Sorry if that sounds stupid, but why isn't Ethernet used for this sort of high bw signaling?

It should be. As soon as video data is in packets, it should be routable over a network like any other data. Give up the custom connectors, custom cables, etc. Need a wireless display? No worries, we can route the data over wifi too. Need 5 displays? Thats what an ethernet switch is for. Screen mirroring? We have multicast. Need a KVM? Well you can probably write a few scripts to change which computer your screen get…

Have you tried VNC over an Ethernet cable at all? What you are proposing is basically having a VNC-like protocol over IP over Ethernet. Now try it out and see how well it works.

To be even more reductive, a thought experiment is to consider the classic USB. Why did people even invent USB in the first place in the 1990s? The first USB had only 12Mbps, not much better than the first Ethernet at 10Mbps which had existed since 1980! Why didn't people who invented USB simply use Ethernet?

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