Using a U2717D connected to a Latitude E7470 via mini-DisplayPort (laptop side) to DisplayPort (monitor side). I have the system configured to extend across both the internal LCD and external monitor. Laptop is running Windows 10 64-bit.
Whenever the laptop puts the screen into sleep mode, the U2717D goes into power save mode, but then wakes up every minute or so with a message "Scanning for signal" on the screen. This behavior completely defeats the purpose of power save mode. If I turn off the monitor, the USB goes away and Windows reverts all open programs to the laptop screen only (as it now sees the monitor as having been removed), so this is not an acceptable solution.
What is the solution to this? How can I get the screen to stay in power save mode until the laptop revives it without the constant scanning for signal?
It should not be doing this. The laptop has to be sending some signal activating the monitor. See page 47. While testing, be sure that the U2717D USB 3.0 upstream cable is NOT connected to the laptop. Just to remove it from the troubleshooting.
Can you replicate the issue when testing a mDP to mDP cable?Latitude E7470 mDP out port --> mDP to mDP cable --> U2717D mDP in port
What happens when you put the laptop into Hibernate rather than Sleep?
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To be clear, the laptop is not sleeping or hibernating, it has been idle so the screen is turned off for power save mode. I don't have an mDP to mDP cable, but have changed to an HDMI cable to see if that makes a difference.
"it has been idle so the screen is turned off"
it = the E7470 or the U2717D?
screen = the E7470 or the U2717D?
"it" is the laptop. When the screensaver starts it puts the screens into power-save mode. Both "screens" are affected (the laptop screen and the U2717D). I really don't think this is an uncommon setup (laptop connecting to an external monitor and using both the laptop screen and monitor as an extended desktop). The problem is that the U2717D keeps waking up and scanning for a signal every few minutes.
I have switched to HDMI and it might be better (it also fixed some problems I was having with sound through the monitor), but this is not a good long-term solution as I plan to connect another U2717D via mini-DP to extend across all three monitors (laptop + U2717D + U2717D). I don't think I can daisy-chain when using HDMI.
Get an exchange. If the replacement monitor does not have the issue, return the original monitor back to Dell. If the replacement monitor has the SAME issue, I doubt that both monitors are defective. I would return the replacement monitor back to Dell. Then look to the computer, video card, video card ports, video card driver, cabling, or the operating system itself as the possible culprit.
I have 2 of these monitors and they both have the same behavior. There is also a lag in audio when running the Windows audio test. I don't have either of these issues when using HDMI. I saw somewhere else that DP is just a big problem in general, so maybe this could be it.