Page 1 of 1

HDMI -> Display Port

Posted: Tue May 15, 2012 4:04 pm
by noroot
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!

Re: HDMI -> Display Port

Posted: Tue May 15, 2012 4:22 pm
by abishur
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 ;-)

Re: HDMI -> Display Port

Posted: Tue May 15, 2012 5:11 pm
by Joe Schmoe
abishur wrote: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 ;-)
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).

Re: HDMI -> Display Port

Posted: Tue May 15, 2012 5:13 pm
by abishur
Joe Schmoe wrote:
abishur wrote: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 ;-)
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!

Re: HDMI -> Display Port

Posted: Tue May 15, 2012 5:16 pm
by noroot
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 ;).

Re: HDMI -> Display Port

Posted: Tue May 15, 2012 6:05 pm
by jamesh
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....

Re: HDMI -> Display Port

Posted: Tue May 15, 2012 6:22 pm
by SN
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....

Re: HDMI -> Display Port

Posted: Tue May 15, 2012 6:24 pm
by Joe Schmoe
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".

Re: HDMI -> Display Port

Posted: Tue May 15, 2012 6:31 pm
by Joe Schmoe
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...

Re: HDMI -> Display Port

Posted: Fri Apr 26, 2013 8:20 am
by suneilbasu
I bought a HDMI to displayport cable an IT DID NOT WORK :cry:
Didn't get a signal at all.

Re: HDMI -> Display Port

Posted: Sat Apr 27, 2013 3:21 am
by abishur
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

Re: HDMI -> Display Port

Posted: Sat May 18, 2013 1:22 pm
by edzieba
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.

Re: HDMI -> Display Port

Posted: Wed Jun 05, 2013 7:16 am
by RoyTxxx
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

Re: HDMI -> Display Port

Posted: Wed Aug 20, 2014 10:31 pm
by ijg2
Tried it, and it did not work on either a B or a B+
:(

Re: HDMI -> Display Port

Posted: Thu Aug 21, 2014 8:49 am
by BMS Doug
Active HDMI to display port adapters are expensive (cheaper to buy a monitor).

Consider buying a 2 port DVI switch (£12.20)

Re: HDMI -> Display Port

Posted: Wed Oct 05, 2016 5:14 am
by Tagar
Has anything changed in the last 2 years?
Is the new Raspberry Pi 3 Model B better in this sense - can it present DP signal into HDMI port?

Re: HDMI -> Display Port

Posted: Wed Oct 05, 2016 7:13 am
by RaTTuS
Tagar wrote:Has anything changed in the last 2 years?
Is the new Raspberry Pi 3 Model B better in this sense - can it present DP signal into HDMI port?
no nothing has changed - the VC4 is still the same - the output is HDMI,
HDMI need a active converter to make it into DP

Re: HDMI -> Display Port

Posted: Tue Apr 23, 2019 5:58 am
by beanfeast
I think something might have changed since this thread was last updated - the cost of active HDMI to Display Port cables has dropped.

I ordered one from Amazon for £24.99 to connect to a 2nd hand HP monitor that I picked up for £5. The one I ordered came with a female DP port and so also required a male - male DP cable to connect it to the monitor.

Because it is an active cable it means your Raspberry Pi (3 B in this case) + cable require two USB ports to provide power, which fortunately wasn't a problem for me because the Pi is powered by a 6 port Anker USB power supply that has free ports.

However this arrangement is not 100% trouble free. There is a niggling annoyance AFTER shutting down the Pi. Once the Pi has been shutdown and the USB power cable has been unplugged from the Pi, the Pi remains powered on (red LED remains illuminated). When the Pi is in this pseudo-shutdown state, it does not reboot if the power cable is reattached to it. It is only once the DP adaptor is also unplugged from the Pi, or the DP adaptor's power cable is unplugged from the PSU that the Pi finally shuts down completely. After re-reading all the comments about the cable on Amazon I noticed that one other person has commented on this behaviour.

Interestingly once the Pi has booted the power cable for the HDMI-DP adaptor can be unplugged from the PSU and the monitor continues to work.

It may be that other HDMI-DP cables do not exhibit this peculiar behaviour. The one I bought can be found at: https://smile.amazon.co.uk/dp/B07G796JF8