How to connect a mini DisplayPort Windows PC with a Thunderbolt iMac I want to use my mid-2011 iMac as a secondary display for my Windows PC.


My iMac features a 1st gen Thunderbolt port, running on macOS Sierra
My Windows PC has a Mini DisplayPort, and is running on windows 10.


My main concern is that (if I understand right), the 'Mini DisplayPort Source to Thunderbolt Monitor' is not guaranteed to work with any kind of cable, and after lots of googling I haven't found a case where it worked.

I know that there are several related answers for this topic, but there are lots of caveats (OS compatibility, Mini DisplayPort to Thunderbolt port limitations), and I'm still not absolutely sure about some details:
- Is it possible?
- What kind of cable do I need to buy? 
- Do I need to use some specific software like AirDisplay?
This is not possible using Apple's hardware and OS.  As per Apple's kbase:


  You need the following to use Target Display Mode:
  
  A Mac notebook or desktop with a Mini DisplayPort or Thunderbolt port. If your Mac has Thunderbolt 3 (USB-C) ports, you can connect it using the Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter.
  
  A Thunderbolt cable or a Mini DisplayPort to Mini DisplayPort cable  
  
  A supported iMac with OS X v10.6.1 or later
  
  See the list below for iMac models that support Target Display Mode, the type of cable you need to connect that model of iMac, and the kind of port you need on your other Mac.


A software solution, such as AirDisplay or Spacedesk, will be your best bet.

You might also be happier removing in to the PC from the Mac as that typically is faster response times than pushing the PC screen to the Mac. Microsoft RD app is quite good running on Mac OS.