2 Posts
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1795
External monitors not working with xps 15 9575 in tent mode with wd19tb dock
I have an XPS 15 9575 laptop with a wd19tb dock and two external p27115q displays. Since I switched to this dock from my unreliable tb16, even though I painstakingly followed all directions, the extended monitors do not work when the laptop screen is flipped, as it is when I use it in tent mode, a must for my setup.
If my laptop is open normally (not in tent or tablet config with the display inverted), all three laptop displays will work, except that one of the displays, currently connected with the HDMI cable, will only offer 1920x1080 as the maximum resolution, not the 4K I can get with the OTHER display, which is connected by display port to mini display port, or on the laptop itself.
I have tried replacing the HDMI cable connected to this monitor with another display port to mini display port cable, but that is either the same result, or that display doesn't work it all, it varies.
My ideal would be to get back to tent mode and all three displays in 4K. 30hz is OK, I am not a gamer, but I do not know how to reduce the refresh rate -- I am currently getting 59hz at 4K on the laptop and DP display, and 59kz on the other display, at 1920x1080.
With the tb16, I had 4K on all three with laptop in tent mode and its display inverted. It was not reliable, with wired keyboard not turning on, displays flashing at the slightest bump, and increasingly only 1 external working.
jphughan
14K Posts
1
May 24th, 2020 21:00
@Max Bean Not sure what's going on with Tent mode specifically, but the reason your second display's resolution is limited is because there are specific cabling requirements when using higher-end display setups -- such as dual 4K. These are explained in the WD19TB manual available on support.dell.com, but basically when you're using a DisplayPort HBR2 system like the XPS 15 9575, if you're running a dual display setup and even one of the displays is 4K 60 Hz, then one display has to be connected to the "downstream" TB3 port at the edge of the dock -- not the USB-C port near the HDMI output. You'd use something like a USB-C to DP cable to make that connection. The other display can be connected to any of the other outputs. The reason for this requirement has to do with how the WD19TB allocates display bandwidth from the attached system across its display outputs. But if you cable your displays that way you'll get both displays running 4K at 60 Hz.
Max Bean
2 Posts
0
May 25th, 2020 10:00
I will get a USB-C to DP cable late today or early tomorrow and let you and the community know how it works out.