Just an update on my ongoing dramas getting a Philips BDM3740 to work as an external monitor through the SP4 dock. All but gave up using the dock and ended up connecting it directly from the SP4 via a mini DP to DP cable.
Still had lots of issues with flickering and blank screens and only being able to get it to work @30Hz. Strangely changing the DP version to 1.1 from 1.2 in the monitor made it more stable and I could run it @ 60Hz but every few days I was still losing audio or not having the monitor wake from sleep (often requiring a complete reboot).
Then my wife's work changed to SP4s and we wanted to use the dock for both devices and just switch out the single cable, leaving the monitor, keyboard and mouse connected to the dock. Well after a few weeks of trying all sorts of things I borrowed a Dell S2817Q and lo and behold it works perfectly being driven from the dock. Runs at full 4k @ 60Hz with no video or audio dropouts and it resumes from sleep every time.
So it looks like it is just going to be easier to swap out the monitor ...
I have a Dell U3415W, sPro4 and Surface dock 1 (firmware 22.214.171.124), I'm using the mDP. It all works just fine after being rebooted (the dock and monitor) but as soon as the surface goes in to power saving mode or you switch the monitor to another input then there's a 50/50 chance the monitor won't work. It's always been like this; just not robust and buggier than a fly strip covered in molasses!
In the Device Manager I can always see under monitors:
So the SPro4 knows the monitor is connected it just doesn't work.
Curious if anyone has any ideas on how to make this more robust. Thanks.
A simple test for my setup is to turn off the Dell monitor and then turn it on again. Even with the "Keep Display On" app running this simple test failed. When I turn the Dell monitor back on I see the Surface screen momentarily go black (and hear the noise that Windows makes when you connect a device) but after about one to two seconds the display on the Surface is switched back on and the Dell Monitor stays black. Try as I will there's no simple way for me to get the Dell monitor running again unless I power cycle the monitor and dock (I tried switching back and forth between inputs). I do use the Dell monitor as a poor mans KVM.
I tried lots of things; the thing that finally appears to have helped is plugging the mDP cable in to the other port on the Surface dock; looking at the dock from the front I see from left to right; an ethernet port, a 3.5mm sound jack, mDP1 and then mDP2. If I use mDP1 I appear to get much more robust behavior than using mDP2. I hope this helps others? I put electrical tape over mDP2 to try and avoid repeating this issue!
I'll also note that dock firmware is up to date as is the surface. I can now power off the monitor, disconnect the dock cable etc. and appear to get consistent results. Phew!
I have the strange problem that when I connect my surface to the monitor or disconnect it, the scaling often is wrong. Internal display is set to 200%. With the monitor it is set to 125% at a x1440 resolution. When I connect to the monitor while the surface is running, the scaling often stays at 200%, which is too big. Only logging off or restarting the device helps then.