lee <l...@yagibdah.de> wrote: > <waben...@gmail.com> writes: > > > lee <l...@yagibdah.de> wrote: > > > >> Hi, > >> > >> I'm getting a black screen during booting, with the last message I > >> can see being that udevevents are being processed. > >> > >> This happens with an NVIDIA GTX770 connected to a 4k display via a > >> display port cable, and only when the monitor is configured to use > >> display port 1.2 rather than 1.1. With 1.1, I can get only 30Hz > >> refresh rate, so I want to use 1.2, which should allow 60. > >> > >> Installed are nvidia-drivers 343.36. > >> > >> Do I need a very special display port cable for this, or what might > >> the issue? Both the graphics card and the monitor should be able > >> to do the full resolution at 60Hz just fine. > > > > You need a DP cable that is able to handle a resolution of 4k@60Hz. > > Not all DP cables can do this. > > Hm, I bought this cable today, so I'd think it should be ok --- but I > didn't explicitly specify that it must be one that does 4k@60. I > didn't know I might have to. > > Is there any way to tell? The sticker on the package only says DP/DP > 2.0m.
It should be certified to DP 1.1a at least. Excerpt from https://web.archive.org/web/20140327103747/http://www.displayport.org/faq/ ---- Q: Where can I buy a DP 1.2 cable? Most of the cables are certified to DP 1.1a. A: The DisplayPort version 1.2 standard was designed to utilize the Standard Display cable. We did this intentionally to avoid customer confusion. A DisplayPort cable is a DisplayPort cable; EXCEPT if it a “reduced bit rate” (or RBR) cable, which is typically a 15m cable designed for projector applications, and they only support up to 1080P; OR if it is an active cable, which will not support the new HBR2 rate introduced in the DP 1.2 standard. So a cable that was tested to meet the DP 1.1a requirments also meets the DP 1.2 requirements. ---- But this is theory. I've made the experience that some cables doesn't work with 4k@60Hz although they are so-called 1.1a/1.2 certified. I've bought four faulty cables before I found the two that I'm using now. One of the faulty cables doesn't work at all at full resolution, the others are working but the picture had a lot of errors and was sometimes black for some seconds. The two cables which I'm using now are a CROMO 41532 (2m length) and a CROMO 41533 (3m length). Do you have the opportunity to test the cable with some other system, e.g. some live system (knoppix?) or some windows system? I would do this first before buying a new cable. -- Regards wabe
