HDMI -> Display Port


15 posts
by noroot » Tue May 15, 2012 4:04 pm
Hi,

I've been using the rpi with the family television, but that's rather limiting. I've got a 1080p capable monitor with only a dvi and displayport, with the dvi already being in use by my computer (it would be nice to have them both connected to the monitor, to allow quick switching).

There are some displayport to dvi adapters for sale (passive), but do they work the other way around too? Thus hdmi to displayport? What would be the cheapest option, the cables I can find are rather expensive (20 euro).

Thanks in advance!
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by abishur » Tue May 15, 2012 4:22 pm
http://www.amazon.com/High-Quality-Blac ... B002CSRF9M

HDMI to DisplayPort. It should work *in theory* but ultimately someone is just going to have to bite the bullet and find out ;-)
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by Joe Schmoe » Tue May 15, 2012 5:11 pm
abishur wrote:http://www.amazon.com/High-Quality-Black-DisplayPort-Cable/dp/B002CSRF9M

HDMI to DisplayPort. It should work *in theory* but ultimately someone is just going to have to bite the bullet and find out ;-)


I think someone authoritative (either Gert or Dom, I think) stated that this didn't work. That it was a "step up" and, in general, you can only do "step down" transformations (at least without active circuitry).

FWIW, I have a cable that goes the other way (DisplayPort -> HDMI) that seems to work pretty well (I use it occasionally to connect my Mac to my HDTV).
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by abishur » Tue May 15, 2012 5:13 pm
Joe Schmoe wrote:
abishur wrote:http://www.amazon.com/High-Quality-Black-DisplayPort-Cable/dp/B002CSRF9M

HDMI to DisplayPort. It should work *in theory* but ultimately someone is just going to have to bite the bullet and find out ;-)


I think someone authoritative (either Gert or Dom, I think) stated that this didn't work. That it was a "step up" and, in general, you can only do "step down" transformations (at least without active circuitry).

FWIW, I have a cable that goes the other way (DisplayPort -> HDMI) that seems to work pretty well (I use it occasionally to connect my Mac to my HDTV).


Good to know!
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by noroot » Tue May 15, 2012 5:16 pm
Oops,

I ordered such a cable minutes ago before refreshing :x. I'll test it anyway, if it works that would be great, otherwise I've lost the bet and I'll have to make friends to give it away ;).
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by jamesh » Tue May 15, 2012 6:05 pm
I was talking to rpi_newbie at lunch time over reheated Indian takeaway (I know how to live) and he told me that you can convert DisplayPort to HDMI but not the other way round. Display port is packet based and HDMI is streamed. Or at least, I think that was what he was saying. I wonder if it was the other way round....
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by SN » Tue May 15, 2012 6:22 pm
Can anyone tell me the POINT in display port? was this an Apple proprietary thing? My HP laptop's got it and I had to buy a Displayport to HDMI convertor to test my HDMI to DVI cable/convertor (I know, I know....) in readiness for the raspi....
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by Joe Schmoe » Tue May 15, 2012 6:24 pm
jamesh wrote:I was talking to rpi_newbie at lunch time over reheated Indian takeaway (I know how to live) and he told me that you can convert DisplayPort to HDMI but not the other way round. Display port is packet based and HDMI is streamed. Or at least, I think that was what he was saying. I wonder if it was the other way round....


That sounds right to me - especially in light of my personal experience (see above).

P.S. Love the comment about "I know how to live".
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by Joe Schmoe » Tue May 15, 2012 6:31 pm
SN wrote:Can anyone tell me the POINT in display port? was this an Apple proprietary thing? My HP laptop's got it and I had to buy a Displayport to HDMI convertor to test my HDMI to DVI cable/convertor (I know, I know....) in readiness for the raspi....


I just read the Wikipedia article on it - you should do likewise.

Although they take pains to avoid saying that it is better than HDMI, it sounds like it is (or, eventually will be). For one thing, it is "royalty free" - where HDMI is not.

In any case, not Apple-specific.

Besides, if they didn't keep switching technologies on us, our economy would go bust. Oh wait, it already has...
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by suneilbasu » Fri Apr 26, 2013 8:20 am
I bought a HDMI to displayport cable an IT DID NOT WORK :cry:
Didn't get a signal at all.
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by abishur » Sat Apr 27, 2013 3:21 am
suneilbasu wrote:I bought a HDMI to displayport cable an IT DID NOT WORK :cry:
Didn't get a signal at all.


Unfortunately, that is expected behavior for *all* hdmi -> displayport applications. Displayport can be easily (and passively) converted to HDMI, but not vise versa
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by edzieba » Sat May 18, 2013 1:22 pm
HDMI -> DP and DP-> HDMI are both possible, using active adapters.
The previously linked adapter is a passive adapter; literally just a box (or cable) with wires linking pins on the DP end to pins on the HDMI end. It will only work if your GPU can output a DP signal from a HDMI port, or (more commonly) a HDMI signal from a DP port. This is usually the case where you have a laptop that can only fit one port on the side, but your GPU can internally output multiple formats and you want to expose all of these through one physical connector.

The Pi, as far as I am aware, can only output HDMI. It doesn't have the internal electronics necessary to output DP over the HDMI port, so cheap passive adapters will not work. Correct me if I'm wrong, I'd love it if the Pi could natively drive the iPad 3/4 retina panel!

Active adaptors (for example) should work fine to convert the Pi's HDMI putput to a DP output.
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by RoyTxxx » Wed Jun 05, 2013 7:16 am
Note that Display Port to HDMI cables will not work the other way.
If someone has evidence to refute this, please let me know as I am also looking for something like this.
Sometimes I want to turn my iMac into a display, and if you can pump Mini Display port in over Thunderbolt, it can do this without you having to set anything.

The cable itself seems to be unlicenced => illegal (as far as the HDMI group are concerned
http://www.expertreviews.co.uk/displays ... ed-invalid

Which does allow a converter / dongle, just not a cable.


Though I did find this (haven't bought this yet though I am tempted):
http://www.markertek.co.uk/Catalog/HDMI ... APTOR-LEAD
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by ijg2 » Wed Aug 20, 2014 10:31 pm
Tried it, and it did not work on either a B or a B+
:(
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by BMS Doug » Thu Aug 21, 2014 8:49 am
Active HDMI to display port adapters are expensive (cheaper to buy a monitor).

Consider buying a 2 port DVI switch (£12.20)
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