U2719DC, U2719D, daisy chain, resolution on second 2048x1080

Do you have the power adapter attached to the XPS 13 9360?

Your setup is correct =

I left the office, so will send the service tag numbers tomorrow (+1 GMT here). They were not purchased directly from Dell. Will fill out the form.

Yes I also have the power adapter attached to my XPS 13-9360. No difference if plugged or not. Yes my setup is according to the illustration. It doesn't "flicker" when i connect it directly to from a PC with DP to DP on screen. I don't have a DP out port in my laptop. That's why I tried with external source which is working fine. By the way, flickering is maybe not the right word, it is more likely a Hz issue due to wrong resolution. If the resolution goes to 2560x1440 60Hz, I am sure it will look sharp and good. So what is the issue then? I assume the mixing of U2719D and U2719DC is not a problem. Do I need another cable? Firmware upgrade on U2719DC screen?

I do not see a firmware update on U2719D driver page.

I do see firmware update M3T106 on the U2719DC driver page. But, you should FIRST open the U2719DC OSD Menu. Go to Others and verify that you don't already have the 7/19/19 M3T106 firmware installed. If you do have an older firmware installed, before installing M3T106, read its installation instructions and add the following;
* Connect the power adapter to the XPS 13-9360
* Disconnect the U2719D from the U2719DC

The fault could also be that the XPS 13-9360 TB3/USB Type-C out port is not sending enough bandwidth through that single USB Type-C to C cable to drive both monitors at 2560x1440 60Hz or that its onboard Intel GPU cannot drive them. Which is why the slaved U2719D is dropping down to 2048x1080 60Hz.

You should verify that the XPS 13-9360 is running the latest BIOS, Chipset, Thunderbolt driver, and Thunderbolt firmware.

Awaiting a response to my previous public troubleshooting reply.

I will check for this now and get back to you

So, i upgraded the firmware on u2719DC to M3T106 (previous M3T103)

I also updated the firmware of BIOS, TB3 etc to latest version on my XPS. I updated every single possible component.

Nothing is helping. Same issue. 

Based on your testing, either a TB3/USB Type-C dock or this =

XPS 13-9360 TB3/USB Type-C out --> retail TB3/USB Type-C to DP cable --> U2719DC DP in port (MST On)

U2719DC DP out port --> U2719DC DP to DP cable --> U2719D DP in port (MST Off)

Hello, 

I have exactly the same set up and same issue. Have had my DC monitor for a while and just purchased the D monitor. The laptop (XPS 13 9360) and both monitors were purchased directly from Dell. Updated BIOS on XPS and firmware on DC, no difference. Can you please help?

If daisy connection won't work, what other solutions are available? Any splitters? 

Thank you,

Mikhail

@speedioDK  and @speedioDK , you are both using systems that only support DisplayPort 1.2/HBR2, not DisplayPort 1.4/HBR3.  When using a DP 1.2 system, there isn't enough bandwidth to run dual QHD over USB-C when also running USB 3.x traffic.  The only way to get enough video bandwidth for that over USB-C is to limit USB data speeds to 2.0.  The U2719DC has an option to configure this.  It's called USB-C Prioritization.  If you set that to "High Resolution" rather than "High Data Speed", the display will set up the USB-C link so all four high speed lanes are allocated to video, with only USB 2.0 data speeds, rather than allocating two high speed lanes to USB 3.x, leaving only two for video, thus cutting video bandwidth in half.  If being limited to USB 2.0 speeds isn't acceptable to you, then you'll need to use a USB-C to DisplayPort cable to carry video (which will cause all four lanes to be allocated to video since you won't have USB data running through that cable at all) and then separately use a USB-C to USB-A cable to carry USB 3.x data.  The only way to run enough video bandwidth for dual QHD plus USB 3.x is either with a system that supports DisplayPort 1.4/HBR3, which your system doesn't, or use Thunderbolt 3, which the display doesn't support.  I wrote an explainer post about the various operating modes of USB-C and their effect on possible display setups here.

If you don't see the USB-C Prioritization option on your U2719DC (it should be directly under the MST option in the on-screen menu), then you have an older revision of the U2719DC that doesn't support it.  In that case, @DELL-Chris M  may be able to help you set up an "unlike exchange" for a newer rev, based on an earlier thread where this came up.

Thank you for your advice, @jphughan (I think you were also replying to me). Wasn't clear on why not enough bandwidth until your explanation of 2 lanes being reserved for USB3.x. Will try the setup with switching to USB 2.0.

@bottezini  Happy to help!

Hi @jphughan, tried setting up USB2.0, but didn't find that option on the DC. Then decided to try 1920x1080 on both monitors, however, DC only allowed to change Desktop Resolution and Active Signal Resolution remained at QHD with no option to update. I think that is what causes unclear picture with some flickering on D. Well, that seems to be a different story - will research what causes it.

Best regards!

@bottezini  Try changing your resolution in Intel HD Graphics Control Panel (or Command Center, depending on driver version).  That might force the active signal resolution to change.

@jphughan - thank you for your continuous support! Was able to change the resolution as you advised, but the issue on D persist. Tried another cable for daisychaining - no difference. When connecting the laptop directly to D, it works fine. Ordered a minidp to dp cable to try with the work laptop in case usb-c cable with XPS 9360 causes issues. Else going to try a usb-c to two hdmi adapter (of course, I'd prefer QHD, but to test that both monitors show consistent picture this way). Looks like the issue is quite common.     

@bottezini  Happy to help, and glad you're all set!  In terms of FHD, if you set 1080p resolution in Windows Display Settings, it's possible that Windows only changed the "desktop resolution" while keeping the "active signal resolution" set to the display's native resolution.  In that case, Windows will be rendering at 1080p but then using GPU upscaling to expand that rendered content to the display's native resolution, so the signal on the wire will still be QHD.  There are some advantages to doing this (no momentary black screen when you change resolutions, ability to run sub-native resolutions on the small handful of displays out there that don't have built-in scaler chips), but one disadvantage is that running a lower resolution doesn't free up any bandwidth on the wire -- which is what you needed.  It's possible that changing the resolution using the Intel Graphics application would have forced the active signal resolution to change, but I haven't tried that.  If you want to see this though, go to Windows Display Settings and click "Advanced display settings".