Why does my Surface Pro 3 not set the correct resolution on my Dell P2815Q after sleep?

[rkin005]

About half the time when my Surface Pro 3 returns from sleep/hibernate it doesn't set the correct resolution on my Dell P2815Q (4k) monitor. Instead I have to right-click on desktop, set resolution, change it from 1024x768 to 3840x2160 and move the monitor relative location to be where I want it. Sometimes it does what it should and recognises that this is the monitor I always use and it uses the settings from before.

I almost never plug in a different monitor, so it's not related to that. I'm plugging in using a mini-displayport to mini-displayport cable. The Dell monitor goes to sleep after a few mins of no signal, so it's possibly something to do with that but I've not experimented thoroughly. Sometimes I need to turn the monitor off and on again to make the monitor wake up / to make the Surface recognise there's a monitor there.

Once my monitor has its resolution configured correctly it's totally fine until the next time I sleep/hibernate.

Any ideas?

thanks,

Rory

 

[surfdock]

This could be an issue with the Dell monitor firmware sending bogus identifying DisplayID information such that the Surface sets a default resolution. I've seen this happen on other monitors and can often be resolved by using an alternate port on the monitor: for example use DisplayPort instead of DVI/HDMI. I don't know if it will help but you can try installing the Dell monitor drivers:
http://www.dell.com/support/home/ed/en/edbsdt1/Drivers/DriversDetails?driverId=N2P0J
http://www.dell.com/support/home/ed/en/edbsdt1/Drivers/DriversDetails?driverId=8WTJH


Are you connecting directly with a DispayPort cable or are you using an HDMI dongle? Whatever you're using, try using the other port on the monitor if you can borrow the right cable from someone. If the symptom continues with try running dispdiag.exe from an admin command prompt when the symptom occurs. Save the .dat file. After you've corrected the resolution, run dispdiag.exe and save another .dat file again and post them here and I'll see if I can help further.

Cheers,
Dan

 

[rkin005]

Thanks Dan. I'm connecting with a mini-DP to mini-DP cable. I was previously using mini-DP to DP and had some problems - can't recall exactly but was probably along these lines - so switched to this one. I'll try swapping back to the DP cable and also try a DP-to-HDMI cable if that doesn't work.

I've installed those drivers & Dell software but the problem still occurs (and the Dell Display Manager seems to sometimes take 25% CPU and cause intermittent machine hangs of about 1sec so I'm not very keen on that!). I should also mention that when returning from sleep my surface doesn't successfully wake the Dell monitor from sleep mode and I need to turn it off and on again. I don't know if this is an issue with the Surface or the monitor or just expected behaviour, nor whether it's related to the main problem I'm reporting.

I'll take the .dat files and upload them here once I've tried the other cables.

Rory

 

[rkin005]

This problem seemed to improve but not be totally solved upon upgrading the drivers. After upgrading to Windows 10 it's almost completely gone - occasionally it doesn't wake the DELL monitor up after waking the SP3, but I don't recall having the wrong resolution issue since Win10.