Dr Strangeport: How I learned to stop worrying and love the Displayport KVMs

[@alan.norbauer]

Your KVM switch saved my work-from-home life as old ConnectPro KVM almost drove me to insanity. Thank you for the brilliant work, Wendell.

[@albertsoliz7018]

Can I ask what model you had and why you didn't like it? And how Level1 improved? I'm thinking of getting the display port 1.4 kvm they had.

[@mahavakyas002]

ConnectPro is trash. spent > $500 for a KVM switch for dual 4K monitors (120hz) and it does NOT work. The USB stuff also kept disconnecting.

[@alibizzle2010]

Wendell's Mom: no Wendell I'm not going to get you a $15k cable tester for Christmas Wendell: but all the other boys have got one, Steve even got a fan tester. So unfair!

[@ghostbirdofprey]

Yeah didn't Linus get a cable tester like 3 months ago?

This was super interesting! A year ago I got a Surface Pro 7 with a usb-c port and DP1.4+dsc support, but after none of the hubs worked for 4K 60Hz I started digging. As it turns out intel had problems with the dsc implementation, and even removed the DP version from ark. It was annoying, and made me question a lot of reviews of the docks and hubs.

[@jlficken]

There's a reason why I bought all of my cables from you when I bought my dual monitor four computer KVM from you. That reason is that I didn't want to have cable issues 🙂

[@karls-g5458]

"This was a quick look" -Wendell I hope one day we get the LONG version.

[@bantinho2480]

This is the first time someone adequately explained to me why some cables are better than others and why even "audiophile" digital cables can have merit. Thank you Wendell and Level1Techs for this!

[@clard52]

Better quality cables *can* have merit, but it should also be noted: that doesn't mean most of them do, especially "audiophile" and similarly marketed stuff. And with digital signals it's usually more obvious when they misbehave, it isn't a case where clarity increases with the quality of the cable. There are broken cables, flaky cables (that work in some conditions but not others), and good cables, that work in all specified modes, basically.

[@MickeyMishra]

Looks like its time to make some Data cables out of Some speaker cables and see how well they hold up to the claims!

[@flyguy1457]

Best thumbnail in the history of thumbnails. Instant thumbs-up

[@futuregootecks]

Thanks for the in-depth analysis Wendell!

[@Dan-Simms]

God, whoever is pairing stock cables that don't work with their own monitors should be shot into space.

[@domantlen6231]

Second to that!

[@ChrispyNut]

That sounds like a life-hack for a cheap trip to space.

[@tommix6733]

...or flushed into a volcano along with the cables.

[@mrwalter1049]

@@tommix6733 I'm in agreement with your proposal.

[@MHBGT]

I was playing Zelda Breath of the Wild on my Nintendo Switch connected to my Dell U2717D via HDMI and encountered a screen blacking out issue in a specific scene. In the early sections of the game, there's a rock monster mini boss battle in one of the Hyrule forest areas. When you deliver a hit, the screen would flash white, which sometimes caused the display to black out/reset. As the Nintendo supplied cable was still connected to my TV, I thought nothing about using the existing HDMI cable plugged into the Dell monitor. Since then I've learnt about cable quality, and that not all HDMI 2.0 / 2.1 cables are as they claim to be. (Bear in mind the Nintendo cable is not even rated at HDMI 2.0, but the quality is much better and has no issues).

[@adamkamieniarz9223]

Great piece of content, please do usbC alt modes and hubs next!

[@TalpaDK]

One of the better commercials I have watched lately :)

[@clawwer4404]

Really cool video.. Seen the graphs what the wires are, but this video really explained everything really well, and went even further .. good job!

[@rriehle]

Thx Wendel - hope to get one of your KVMs. Was hoping to hear more about the actual KVM, but still interesting about the cables.

[@MegaAshabasha]

I am just a lowly simpleton, but this video has motivated me to learn the science of the things you speak of...thank the gods my good man!!!

[@Kurukx]

I love how nerdy Wendel is ... $15k cable tester :P

[@SirHackaL0t.]

Possibly because Linus bought one for testing HDMI cables.

[@radomane]

@@SirHackaL0t. Possibly because Wendel develops display port KVM, and this equipment is for that development

[@MrV1NC3N7V3G4]

Did he buy the one that Linus bought after Linus made his video?

[@joe_ferreira]

@@MrV1NC3N7V3G4 Linus bought one for HDMI

[@SirHackaL0t.]

@@MrV1NC3N7V3G4 The test screens look identical.

[@whosscruffylookin95]

I just started down the DisplayPort KVM rabbit hole yesterday. Perfect timing.

[@aNotoriousPhD]

thank you for all that you do wendell!

[@robsquared2]

I'm so glad you took the effort to do this stuff. I just bought one of your KVMs because my expensive amazon one started crapping out after a year of use and never handled 120hz 5120x1440 correctly.

[@christopherjackson2157]

I had to watch that twice before I felt I was really following. There was a lot of info packed into that video. Certainly does explain a few issues I've encountered with display adapters

[@crispysilicon]

Well that was... the bomb! XD Can't wait to see that front panel testing.

[@armondkuehn1278]

So glad to see someone elses office is just as messy as mine!

[@szaszm_]

25:57 Regarding Apple and hotplug: I think pedantry only describes situations where the pedant is correct, but doesn't apply to those who are wrong. Apple seems to be using the protocol incorrectly if I understand correctly, so that's not pedantry. (This comment is more like it, unless I'm wrong somewhere.) Unrelated Q: Can I drive a 4K120 TV with HDMI inputs only with your KVM switch, switching between a desktop PC (has DP and HDMI) and a laptop with Thunderbolt or USB-C + DP? VRR would be an optional nice to have.

[@bw_merlin]

I enjoyed this, understood some of it and other parts went over my head.

[@d00dEEE]

Awesome video, Wendell. Sending it off to all my techie kids, making sure they watch it...

[@lightfire33]

I dream of a future, where all hardware manufacturers have this level of passion, to make products that do not suck. Alas, greed would never allow it, but I can dream, dammit!

[@robd3747]

That thumbnail is gold.

[@TolaGarf]

Wonderful video. That thing with a DP cable working with one GPU and not with another, I tried that and mystery explained finally! Would love to see a video detailing how Thunderbolt 4 works in combination with a discrete GPU with the Alder Lake platform when the motherboard has no DP IN port at all. I can't seem to find any information on this how it works, if it works at all?

[@jellorelic]

Agreed! Very nice to see some actual information about what can be going on under the hood on some of those classic "This cable just hates this video card/monitor/usb port" type situations.

[@stevenkewlkid]

More, more, more! I love this content.

[@zyntax81]

I love it when Wendell goes full Wendell !

[@theInsaneRodent]

8:25 RX Vega 64 has poor display port link training? I see. I suspected my issue with my Valve Index was a link training issue, because I can unplug the display port cable and plug it back in or power off the headset and turn it back on until the link works and then it works fine for the entire session. It is interesting to know that there is a potential physical layer tx parameter adjustment for this that is exposed in the driver rather than needing to fumble around behind my computer with my headset on half the times that I start VR. (The issue also did not happen with my original HMD, only with the warranty replacement one I got after I broke the first one)

[@andrey7268]

14:01 DSC is not lossless. It is marketed as "visually lossless", meaning that it is actually lossy but the losses are not (supposed to be) noticeable by the human eye.

[@bengrant7654]

DSC also adds much less than one frame of latency. So less than 8.3333 ms if you're at 120Hz.

[@snowwsquire]

@@bengrant7654 he never said it added a frame, he just compared the amount of latency it adds to the amount of time it takes the display to refresh, the explanation was kinda unclear

[@enregistreur]

The video I didn't know I needed, and that I was interested in! 😅

[@heimvar]

10/10 recommend thick tip pens so in the future if you ever do these again we can see these a little better at a lower resolution (a mobile data user). On a side note the display port cable that came with my monitor even has blackout issues at 1080P 165 Hz. I wonder if it's a decent cable or not

[@TheBlackPaulMuadDib]

Awesome, explanation.

[@h4X0r99221]

Amazin video Level1 Team!

[@zackkertzman7709]

26:35 "Ahh, yes! Ze terroir of zees chip will compliment perfectly ze frequency response character of my cable!" *Chef's kiss*

[@StaK_1980]

The title alone is worth at thumbs up! :-)

[@LanceThumping]

With all the similarity between all these different devices, it's a little surprising we don't have some unified design yet with the only real differences are the run lengths and maybe connector to prevent compatibility issues. Like you said, if everything is reinventing PCIe, it'd be really cool if they just switched to using different versions of PCIe. Then instead of trying to take a Displayport cable and find a way to run USB on it, we'd just change from a PCIe3x1 cable to a PCIe3x2 cable for example. Though there are almost certainly issues with that method that I'm unaware of, it just would be cool to get all this shit on the same page.

[@greebatic]

Thanks professor

[@jonbetts8473]

Man, can't wait until the USB-C with power delivery KVMs are released!!! Save us Wendell!

[@leviathanpriim3951]

thanks Wendell

[@hootis8]

This is the video I never knew I needed

[@wobblysauce]

Another interesting video, some of the best cables I have are the cheapest ones you could buy.

[@murtadha96]

Thank you Wendell. Can you make an in-depth video about the abysmal state of dongles and why most of them are so bad (including multi-hundred dollars ones)?

[@DrewMarold]

That was very informative. I recently got an RTX 3080 and I've been having issues with random noise and screen blanking. I tried all the software stuff on the forums but nothing helped. I just swapped out the cable with one I had on hand and so far no issues, but I also ordered (what I hope is) a higher quality one.

[@m4nc1n1]

Good job!

[@0M9H4X_Neckbeard]

fantastic video!

[@kwinzman]

You should have mentioned what common mode noise is when you talked about the ferrites.

[@Level1Techs]

Yeah there's a couple rabbit holes I probably should have pointed out at least

[@kwinzman]

@@Level1Techs Yeah :-) I know there's only so much you can fit into one video. But that's crucial to understand why the bead doesn't or hardly interferes with the high frequency data signals in Displayport, because they all use differential signaling with two wires each (including the AUX channel).

[@HeyImGaminOverHere]

I would love to hear a drunk Wendell rant on display port cables now!

[@aldimore]

Nice Tech Talk Wendell. I have been using synergy for allowing me to move between my 3 computers. Last time I used a kvm was a decade ago. Maybe I should consider looking at one of your offerings some day.

[@003bobjones]

I was able to use to the infomation in this to help make a screen that I use work better when power it on or if. Turns out garabge or damage cable. The cable it using is at least 4 years old. Running a 2k 60 hz screen

[@barryman5000]

Any time he goes to the whiteboard I'm excited.

[@Chris-uh1qr]

Thanks. Good explanation. Display port is a complicated protocol. Could you do a brake down explanation for HDMI?

[@jorelplay8738]

I'd also like an explanation on hdmi, I always felt it is more reliable than DP

[@Chris-uh1qr]

@@jorelplay8738 HDMI has a lot of signal negotiating due to the copyright protection and HDMI licensing on the chipset (I believe this is why. A good 1h long video would be ace) Also I bit on the pros and cons of the two systems.

[@GS-xp5jq]

Great information :)

[@4brigger]

pre-emphasis indeed; best buy has been solid as far as what OSD tells me on 1.4DP; mines monitors are the ones what with gsync qualifications (stickers) so they might be lieung like a cheap rug maybe?

[@solidreactor]

Can't wait for optical cables to be the standard for DP and other high bandwidth standards/cables

[@PhoeniXfromNL]

hearing what all could go wrong between the graphics card and the monitor, really reminded me off the interview with Greg Kroah-Hartman, it's a freaking miracle stuff works lol

[@marvintpandroid2213]

Is it still March?

[@owlmostdead9492]

Very good video, thank you

[@Willhemmens]

The rack mount fan noise in the background couldn't be more Wendell.

[@kelownatechkid]

Oh god I hope you/someone is working on that 'lunacy' lol it sounds super useful

[@deth3021]

eDP was designed as a replacement for lvds displays in laptops... Which is where it mainly gets used afaik. Using it for external displays was never the intent afaik. I mean that's why it is called an embedded display port eDP.

[@abavariannormiepleb9470]

Any news regarding active DisplayPort 1.4-to-HDMI 2.1 adapters that actually work? Don’t even care about VRR anymore, just looking for 4K/UHD 120 Hz/Full-Range RGB so no chroma subsampling. Edit: Don’t post a comment before completely watching a video 🙃

[@Level1Techs]

Hehe 😋

[@paulthebeardedonedowning6820]

I really like this video I learnt something pretty cool

[@mspencerl87]

You do so well at disseminating information. I think its time to make the video. Explaining how Americans have paid for nationwide fiber! Because I honestly don't know the when, how, or why. But would really like to have you explain it to us!

[@gautambhatnagar4765]

I just gave up and went for optical displayport cables, which solved all the weird issues I was getting

[@cdx77]

Thanks for this, good brain food 😋

[@CreativityNull]

So the cable being broken is way more complicated than you think... But the solution is the same when having problems with video peripherals: 1st step of troubleshooting after narrowing it down to just the screen, replace the cable with a known working cable (with this video making me amend it with "... In the same configuration as the problem system.")

[@magneticshrimp7429]

speaking of fun DisplayPort stuff. If I connect my monitor to my computer (via a amd polaris card) the post code display on the motherboard somehow lights up even if my computer is not connected to power, as long as my monitor has power. wonder if the 5v's are interconnected over a 20th pin ;)

[@msor6108]

The 20th pin has caused me so much problems. Even when I was using 1080 60hz displays a few years ago, I had display port cable issues.

[@cromefire_]

eDP is in use in pretty much most PC laptops as far as I know. I mean that's where you'd expect a slim screen and brightness and color controls from software/OS/GPU.

[@draco10111b]

I think smartphones as well. Though it's been a few years since I remember reading about it. Basically most places where there's an integrated screen and power is a concern.

[@Knirin]

Most pc laptops use lvds not eDP.

[@cromefire_]

@@Knirin Well eDP is the replacement for LVDS so I think in the higher end devices that need higher bitrates need to use eDP

[@cdoublejj]

THIS is why i patreon

[@Ljosi]

I'm really jealous of this mans IQ

[@ramin3963]

Hi Wendel, could you also educate us about HDMI? Specifically how does USB C to HDMI adaptors work. And if you know a good adaptor please let me know. Thanks.

[@Tiwo1991]

When i get up from my desk chair, the spring in the chair makes this pop. It causes my screens on my desk to flicker of and on again that are connected via displayport to my laptop.

[@omgMBP]

ah you got the tester! good job.

[@curtisbme]

Displayport 2.0 will fix everything and all devices will work perfectly forever and you won't have a ton of new problems on top of the 1.2 & 1.4 headaches..

[@annihilatorg]

Makes sense now why my cable matters adapter/dock thing can do 4k@60 over usb-C with usb2.0 for peripherals. They must use that AUX channel for the usb2.0 data. Every other usb3.0 enabled adapter only supported lower resolutions and usb 3.0.

[@SirReptitious]

Whew! Thank fuck I get by with just using HDMI on my PC/monitor and PS3/TV. ;-) But as usual, I still watched the whole video because I never want to stop learning, and there is always a small chance that I may be able to help someone in the future who uses displayport.

[@Quick_Sa_Fugim]

My Polaris also has a shady DP connection as I only have a good signal only if I downclock + downpower the card by 5-9%. They cheaped out on it and it took me years of troubleshooting to find the exact way to eliminate the short black screens. The emphasis change at driver level did not made any impact.

[@browskie]

the memes are strong with this one:) love this show

[@goffe2282]

Ahh, A white board presentation. I miss those :(.

[@markchambers7147]

I had a DisplayPort cable that would not work when the card was in a vertical Mount. Took weeks to figure it was the cable and. It the pcie. Extension

[@Ziggurat1]

What about a USB-C or Thunderbolt dock + dual head KVM for displayport. I mean for one USB-C laptop and one Displayport Desktop

[@alexro13]

So then what's the point of the power pin, if it must not be connected? If it's useless, it could be dropped and we would have a (slightly) smaller connector. What am I missing?

[@jurepecar9092]

One question: when will servers get rid of VGA + USB A combo and replace it with single USB C carrying both KVM and usb storage? This way server vendors could save a couple of square inches of area on the back of the server and dedicate that to better airflow instead. I understand that ASPEED 2600 already supports DP ?

[@dcphillips1991]

I gave up trying to use DP for my Gigabyte M32U, it would just randomly black screen using it every 10-20 minutes. The HDMI seems to work fine, I'm not sure whether it is the cables, the monitor, or the GPU.

[@mnyoupass]

Have you ever thought about finding a display port manufacturer which you can contract with to make level 1 techs dp cables? That way you have a reliable source of dp cables!

[@Level1Techs]

store.level1techs.com/products/display-port-14-cables-120-cm-amp-200-cm

[@daemonbyte]

Does anyone know of a device where you can connect 2 laptops, via thunderbolt to it and it has 1 thunderbolt out which you can connect to a dock? I have a thunderbolt dock that connects everything to my personal laptop but then I have a work laptop. And currently I have to keep unplugging the dock and moving the cable to the other device and plugging it in. Be nice if I could just hit a button and it switch between them. But I can't seem to find anyone that makes such a device

[@plaisthos]

I really want a cable tester to my own cables. Then I look at this of the cable tester (which is still cheap for this kind of equipment) and decide that I can probably still order 10 different Displayport cables from Amazon and switch tem around until I have one that work. Would be interesting to know if there are are probe point in the KVM switches where you could hook up your oscilloscope to see the channel and if that gives any insight.

[@TalpaDK]

Me too... I would however also settle for a friend owning one close by :) The problem with just buying lots of cable (apart from supporting manufactures that produce crap) you don't quite know why a given setup is working or not...

[@daveninjaneuro7089]

So when is the kvm dp 1.4 stuff going back in stock?

[@TheBackyardChemist]

No I am quite sure I do want to control my monitor from the os. I installed twinkle tray

[@user-rc9jf8ng2k]

TEST ALL THE CABLES!!

[@jwdickieson]

Dear God Wendell the red on red is just a floating head and arms

[@dimonor]

So, when can I buy Level1 certified cables?

[@TheMurrut]

Why no Optic Fiber monitor cables?

[@Teknickel_ftw]

Over the years I have had a lot of issues with hdmi and dvi displays on nvidia cards. I am sure that has a rabbit hole of its own.

[@shards.v1]

I sometimes forget Wendell at some point was taught the wealth of knowledge he possesses, otherwise I naturally assume it was simply imbued upon him at birth

[@tonnylins]

It came as an builtin OS feature, his soul is full of learning and wisdom potential!

[@spiralout112]

So I take it display port does not handle audio as well? Ive been looking for a way to have my desktop in my rack in the other room and have a cable send display, audio and usb without too much latency. Then I could just have one little box or two, a monitor, kb&m, an amplifier & speakers in my office and that's it. All of which would be fanless and gloriously silent. So far it seems the cables lack USB and most of the boxes don't have high enough resolution 1440p uw@120hz, or only support either audio or USB. Love.to hear if anyone has suggestions, and might make for a great video topic too!

[@Level1Techs]

Dp handles audio, that's at the protocol level

[@spiralout112]

@@Level1Techs Cool I'll have to look into it! I've been mainly focusing on hdmi or those HDMI over cat5 boxes which don't really seem to have gaming in mind, and are pretty pricy for the good ones. That would be amazing if DP can pull it off!

[@vincei4252]

It does have audio, however, for some reason ubuntu doesn't auto select the audio on the cable from my Nvidia card. I have to go into the desktop settings everytime after a boot to change it to the DP channel. Any clues, Wendell ?

[@MaxPrehl]

Spiralout, for your setup you should see if you could do something like Linus did. He's using Thunderbolt over fiber and has a dock at his desk that breaks out DP, and several USBs. However, he uses a usb audio interface on his desk, so not sure if that would work for you.