Intel HD520: Display Becomes "Digital Flat Panel (640x480 60Hz)" After Display Sleep

[KarolPrzybyszewski]

I have the following configuration:
T460 connected to 2 monitors via displayport (through the Lenovo 40A2 ultra dock). One is an Acer and the other (troublesome one) is an HP x27q. Both usually run at 59hz at 2560x1440 resolution.

The issue begins when the computer displays go to sleep. A device disconnect sound plays as soon as this happens and once woken up the HP x27q is no longer detected as such and instead shows up in device manager as "Digital Flat Panel (640x480 60Hz)" and will not allow me to change resolution. After that the only fix is to unplug the displayport cable and plug it back in or to power cycle the monitor.

I have tried swapping ports for both monitors and cables but the behavior always follows the monitor so it appears to be a compatibility issue between the Intel iGPU and this monitor. I also tried using two other monitors and it works fine.

I have not had this issue with Nvidia or AMD GPUs on this monitor and so I am deducing that it must have something to do with the Intel GPU/driver.

I am attaching the intel ssu logs both before and after sleep to this post. Hopefully this helps diagnose the issue. I have noticed the device ID remains correct, so its almost like something in the system (Intel driver?) is incorrectly assigning a monitor driver after sleep. Like I said. I have never seen this issue on AMD or Nvidia with the same monitor.

The issue persists even if it is the only monitor attached to the machine. Please advise.

[DeividA_Intel]

Hello KarolPrzybyszewski,  

Thank you for posting on the Intel® communities. I am sorry to know that you are having issues with your Intel® HD Graphics 520.   

In order to better assist you, please provide the following:  

1. To confirm, is the Lenovo T460 Laptop (ThinkPad) the model of your laptop?

2. What is the brand and model name of your processor?

3. To confirm, when the HP monitor is connected to the laptop, are you using a straight connection or adapters?

4. Is this issue present only with Intel drivers or also with the laptop manufacturer drivers?

5. What is the BIOS version installed?

6. Have you reported this behavior to the laptop manufacturer?

Regards,  

Deivid A.  

Intel Customer Support Technician

[DeividA_Intel]

Hello KarolPrzybyszewski,  

Were you able to check the previous post and get the information requested? Please let me know if you need more assistance.   

Regards,  

Deivid A.  

Intel Customer Support Technician  

[DeividA_Intel]

Hello KarolPrzybyszewski,  

I was checking your thread and see that we have not heard back from you.  

I’m going to close your post, but if you need further assistance, please do not hesitate to create a new thread. 

Regards,  

Deivid A.  

Intel Customer Support Technician