09-11-2016 02:26 PM
09-11-2016 06:40 PM
Lenovo promises that 3x1920x1200@60Hz will definitely work with the dock - https://support.lenovo.com/ca/en/documents/pd029622 , and with M3000 + dock they do work 100% reliably for me.
For the extra 2 monitors (to reach Lenovo claim of 5 in total) can use Thunderbolt 3->DisplayPort adapter, which are plenty on Amazon at ~$30/piece. That's the only way to hookup more than one 4K@60Hz monitor to P70, for example.
09-11-2016 07:44 PM
09-12-2016 11:33 AM - edited 09-12-2016 11:36 AM
Thanks; that link says a lot more than I could find before I bought the thing. When I was looking into them early-on, I saw in similar documentation that the dock supports two displays up to 3840*2160@60Hz, but never saw any mention that the HDMI is at 30Hz for anything above 1080p (though that was expected) or that the DVI connector was not dual-link (this came as a surprise, and is only implied by the resolution limit in the current table). I'm glad they finally filled in the details better. How did you manage to connect a 1920*1200 panel to the analogue port?
The "new" Workstation dock was a major disappointment. Lenovo later revised/clarified the statement "dock supports two displays up to 3840*2160@60Hz" , as that does not work. ALL dock video connections together must be within bandwidth of one 4K@60Hz. And once it gets close to that number (and with your monitor resolution it seems very close, if not slightly exceeding it), things might get unreliable.
So I ended up not using the dock where I needed 2x4K monitors (and connect the laptop directly with 1x miniDp , 1x Thunderbolt3->DisplayPort adapter), and moved the dock to another location where there are 3x1920x1200 monitors on my desk (via VGA, DisplayPort and DVI on the dock). No problems with the resolution sticking at either place, and Windows 10 picks up configuration automatically.
09-12-2016 07:28 PM
(2560 * 1600) + (1200 * 1600) == 6016000
(3840 * 2160) == 8294400
(4096 * 2560) == 10485760
(3840 * 2160) + (1920 * 1200) == 10598400
On the page you referenced, Lenovo claims it supports 3840*2160 + 1920*1200 both at 60Hz, so 6M pixels total on my displays verus 10M pixel limit has me pretty well under the limit (about 60%). Based upon that, it can even take what I'd like to see as my next display -- 4096 * 2560 (though I don't expect that to work any better than the 1200*1600 panel).
Since it still insistently mis-sets the resolution even with only the 1200*1600 display, I don't think it has to do with the bandwidth limit. I don't think it is the display either, or the connection to it, since several other machines also running Windows 7 detect the display and use it correctly. If I connect this panel through an active DP to DL-DVI adapter (like I'm using for the 2560*1600 panel) then it works. Even if I use a passive adapter on the onboard mini-DP port, it just works. It just doesn't work on the dock's DVI port or using simple wired HDMI to DVI adapter or simple wired DP to DVI adapter with the dock. The dock just doesn't like anything but DP, which is hardly a surprise since probing it looks like it has a single DP connection to the PC that is split on the dock into three ports -- VGA, DP+SL-DVI, DP+HDMI. I'm convinved this DP splitter is the source of all of these display issues. The dock firmware release notes make me suspect it is the source of the reboot hang I'm seeing, too.
I've finally coerced it to work well enough for now on this front, using an active DP to DL-DVI adapter like I have with the 2560*1600 panel (both powered by an external power source), and I've suspended the dock and PC over a mesh frame with fans blowing up on the bottom of the dock and PC to keep it cool enough to not die under heavy load before the onboard fans get a chance to kick up to full RPM, so that much is covered, too. Funny that I don't have the shutdown problems unless it's in the dock, even with the same devices connected and running the same code, and that forcing cool air up the assembly of dock and PC seems to resolve this problem. Maybe the video being on the left side and the dock almost completely obscuring the intake on that side has something to do with the shutdown problem?
Now if I could just figure out what I need to do or hack to make it where 'rebooting' with it in the dock does not cause it to hang on the screen just before the Lenovo logo (or diagnostics screen) is displayed. It's as easy to do a shutdown and then hit the power switch on the dock as restart (and then hit the power button on the dock). I don't see this problem either if it's not docked.
I'm quite disappointed. Out of ten, I might rate the dock a 2 or 3. It gets that many points because it does something basic I expect from a dock -- plop the machine down on it and it connects power, video, audio, peripherals. In much every other way it's disappointing.
Pity this dock seems to be the 'best' such option for the machine. I expect the display pixel count limitation of 10M pixels at 60Hz is stuck (the dock connector on the PC) but it would be nice to have a dock that doesn't suffer the same other restrictions and problems, so I can hope Lenovo may one day do a revision that takes into account the problems with this one. Not holding my breath though; Expecting the P70 will sell as well as the W700 long term if this is the best they can do.
09-13-2016 04:52 AM
Thank you Zac_S for initiating this thread. Your strrong opinions finally nudged me to abandon my own Workstation Dock after struggling for months to resolve display issues. In the latest incident my P70 was refusing to recognize the new monitor's max display resolution (2560x1440) but now it boots up like a charm. I couldn't be happier. I even took the opportunity to follow your advice and prop up the laptop to maximize the underneath airflow and it is running cooler.