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Comment by salamandersauce | Hacker News Reader

It's also bizarre to me that pretty much every affordable USB C dongle that has both USB and video out have the video out be HDMI (okay there is a few with VGA but good luck if you want DVI or DP) despite USB C typically using DP alt mode. Why not skip the conversion to HDMI and give me DP with its extra bandwidth?

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Its probably because they're not actually doing USB-C alternate DP mode but probably using a DisplayLink chipset. Its a system of doing graphics over USB and IIRC supports HDMI by default.

No, the vast majority of dongles just have a DP-to-HDMI chip

DisplayLink requires extra drivers, these dongles don’t.

FWIW I’ve been using 2 thunderbolt to display port cables to drive 2 4K60 monitors since 2016. The cables cost me roughly $10 CAD each. I guess I was just lucky?

Link?

Thunderbolt to DisplayPort cables aren't a thing. Thunderbolt 2 was already a Mini DisplayPort connector that used normal cables for that; Thunderbolt 3 uses USB Type C and you can get USB C DisplayPort cables (using DP alt mode). No Thunderbolt features involved there either.

Converting Thunderbolt to DisplayPort is technically possible, but completely pointless because both TB2 and TB3 are natively DisplayPort compatible, at both protocol and connector level.

> Converting Thunderbolt to DisplayPort is technically possible, but completely pointless because both TB2 and TB3 are natively DisplayPort compatible, at both protocol and connector level.

One exception: it's useful for a Thunderbolt Dock to have a Thunderbolt connection to the host system, while offering another Thunderbolt port that can emit a standard, un-encapsulated DisplayPort signal. But for an adapter with none of the other ports offered by a dock, it is generally pointless.

Yes, I meant a straight adapter only; of course it is useful for a Thunderbolt dock to have a DisplayPort output, among other ports.

I would suggest looking into the Dell DA310. It has all three (VGA, HDMI and DisplayPort). 60hz 4K over both HDMI and DP

Might be the difference between HDMI 2.0 and HDMI 1.4. That tripped me up a few times. HDMI 1.4 can only handle 4K@30Hz.

> Why not skip the conversion to HDMI and give me DP with its extra bandwidth?

Because nobody in China uses DP

Sadly "nobody" anywhere uses DP, as in any random TV or projector or cheap monitor you'd encounter uses HDMI. DP only took off for serious monitors.

Which is weird because every $200-400 monitor I’ve bought in the past decade-ish has been DP first with maybe an HDMI port.

Yeah, that already counts as "serious" :) Cheapest 1080p ones don't all come with DP

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