12 Posts
0
2368
U2417H, acts weird with both mDP and HDMI connected
I have several U2417H monitors. All don't seem to like being connected to both DP (or mDP) and HDMI inputs (from the same PC...i.e both carry signals) at the same time. Detailed description: with monitor turned off, both DP and HDMI are connected to monitor. Turn PC on, monitor on (set to HDMI input), monitor displays partial desktop background image and machine is not responsive. In order to use HDMI input, DP MUST be disconnected from PC! However, turning the monitor on with both DP and HDMI connected to PC and monitors set to DP input does not cause this weird behavior to happen! So in summary, it feels like when both inputs are connected, and DP is not set as the input source, monitors goes crazy! FYI, I have four of these monitors connected using MST. This behavior happens even when 3 of the 4 are shut off. Windows even reports seeing two monitors when both the DP and HDMI cables are connected. Once I disconnect one of the two, it sees one. Also, there is little documentation on the "Auto Select" feature, which is supposed to automatically pick the active input source, but I found that it does not do so. When I disconnect the HDMI cable from PC. I have to manually pick DP input on the monitor. So what good is "auto select" for?
Thanks
DELL-Chris M
Community Manager
Community Manager
•
54.2K Posts
0
October 4th, 2018 11:00
"the same PC has two outputs and both are connected to the same monitor at the same time."
* That makes no sense to me? In a single PC/single monitor setup, the PC video card should only have one monitor cable attached to it. In what usage model would you need both connected?
If we look at the U2417H User's Guide page 27, it shows single PC/single monitor setups;
PC HDMI out port --> HDMI to HDMI cable --> U2417H HDMI in port
Ryzen GTX 1080 HDMI out port --> HDMI to HDMI cable --> U2417H HDMI in port
-or-
PC DP out port --> DP to mDP cable --> U2417H mDP in port
Ryzen GTX 1080 DP out port --> DP to mDP cable --> U2417H DP in port
The User's Guide never discusses all video card out ports connected to all U2417H in ports at the same time.
DELL-Chris M
Community Manager
Community Manager
•
54.2K Posts
0
September 28th, 2018 06:00
* Explain in detail how four U2417H are connected to that one PC list all ports used and cabling
* What PC model?
* What operating system?
* What video card?
* List all of the video out ports on the video card
jad12
12 Posts
0
September 28th, 2018 15:00
tell you what.....forget about daisy chaining at all......just focus on pc-->mon1 through two cables (HDMI AND DP) at the same time.
why does the monitor act up when i select input source as DP or HDMI and have that cable connected and active when the other cable is connected too....in other words why must i disconnect the cable i didn't select as input source on the monitor?
this behaviour is also observed on my custom built ryzen machine with gtx 1080
jad12
12 Posts
0
September 28th, 2018 15:00
forget about the 4 monitors (mons for short)....let's focus on two mons and the PC.
cabling as follows:
laptop (dell 7480, has both DP over usbc and HDMI ports)...both connected to mon1--> mon1 (mst on) connected to mon2 via DP cable (mon2 mst off).
usage case:
mon 2 is turned off...only mon1 and PC turned on: when both DP and HDMI cable are connected to mon1, it acts weird and does not display desktop properly. either HDMI or DP cable has to be disconnected from laptop AND the correct input source must be be selected on mon1 for it to display stuff correctly.....so two failures by mon1: 1) acting weird and not displaying desktop correctly when it is set to HDMI input OR DP input AND it is connected to both cables at the same time. 2) failure to "Auto Select" the active input source once the other cable has been removed.
don't worry about the 4 mons....i daisy chain 2 mons only to each PC...i have two PCs...sorry for the confusion
jad12
12 Posts
0
September 28th, 2018 16:00
windows 10 btw
DELL-Chris M
Community Manager
Community Manager
•
54.2K Posts
0
September 29th, 2018 04:00
Below are setups that should work. Now expand on those and tell me what you are trying to do.
First PC setup, two monitors in daisy chain =
Latitude 7480 USB Type-C out port --> USB Type-C to DP cable --> #1 U2417H DP in port MST On
#1 U2417H DP out port --> DP to mDP cable --> #2 U2417H mDP in port MST Off
Second PC setup, two monitors in daisy chain =
Ryzen GTX 1080 DP out port --> DP to mDP cable --> #1 U2417H DP in port MST On
#1 U2417H DP out port --> DP to mDP cable --> #2 U2417H mDP in port MST Off
Dual PC setup to one monitor =
Latitude 7480 USB Type-C out port --> USB Type-C to DP cable --> #1 U2417H DP in port MST Off
Ryzen GTX 1080 DP out port --> DP to mDP cable --> #1 U2417H mDP in port MST Off
Latitude 7480 USB Type-C out port --> USB Type-C to DP cable --> #1 U2417H DP in port MST Off
Ryzen GTX 1080 HDMI out port --> HDMI to HDMI cable --> #1 U2417H HDMI in port MST Off
Latitude 7480 HDMI out port --> HDMI to HDMI cable --> #1 U2417H HDMI in port MST Off
Ryzen GTX 1080 DP out port --> DP to mDP cable --> #1 U2417H mDP in port MST Off
jad12
12 Posts
0
October 3rd, 2018 18:00
sorry for the late reply:
none of the setups you described fits what i am trying to do....here it is again:
Ryzen GTX 1080 DP out port --> DP to mDP cable --> #1 U2417H DP in port
Ryzen GTX 1080 HDMI out port --> HDMI to HDMI cable --> #1 U2417H HDMI in port
(forget about Daisy chaining for now)
the same PC has two outputs and both are connected to the same monitor at the same time. I switch input signal from the monitor itself by selecting either HMDI or DP/mDP....the problem is, the monitor behaves weird unless i physically disconnect one of the input cables.
please let me know if this is not clear
jad12
12 Posts
0
October 4th, 2018 18:00
got it...not doable
thanks