lee <l...@yagibdah.de> wrote: > <waben...@gmail.com> writes: > > > 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. > > Thank you very much for all the info! > > I finally got a cable that works. It's from Delock and says 82771 on > the back of the package where the EAN code is. I like it, it seems to > be good quality, and most importantly, it works.
Then you really had luck. I had two faulty cables from Delock and I decided not to buy a cable from Delock again. > However, I can see the BIOS and the boot manager menu, then during > booting, the screen goes black and the monitor says "no signal" > (probably when the nvidia module is loaded). So I logged in blindly > and started X11 and got a picture again. > > The monitor info says 4k@60Hz in the BIOS and when X11 is running. So > there must be some setting which causes the graphics card to blank out > on the console. > > Any idea what that could be? That's strange. I would understand a message like "Frequencies out of range" or something like that. But "No signal" indicates, that the monitor gets no signal at all. What happens when you switch from X to text console (Alt + Strg + F1)? -- Regards wabe
