The problem:

I was asked to clone Dell XPS 15 (l502x) display to its HDMI output, which turned out to be harder than it seemed. You can extend the desktop with no problem, but for cloning you may get in trouble.

The situation:

First thing to know, this laptop has two video controllers, and apparently this is one of the causes to the problem. The display and HDMI outputs are coming from different sources: display is connected to the Intel HD Graphics, while HDMI is connected to the NVIDIA GeForce GT.

Basically windows itself doesn’t know what’s going on and cannot handle the situation on its own , it’s NVIDIA’s driver responsibility to manage the process. Here comes the second cause, the NVIDIA driver originally installed on the system failed to do so (and the laptop owner told me he even updated NVIDIA driver through NVIDIA website, but no difference).

Seemingly you can clone the display to the Mini-DisplayPort (next to the HDMI port) without a problem, as they are both connected to the Intel HD Graphics.

The solution:

As mentioned in a post in Dell community the difficulty should be solved by updating to NVIDIA’s driver found on Dell website, which wasn’t the case for the laptop owner when he tried (and since then in every reboot windows was trying to download a High Definition Audio Driver from Windows Update). I installed NVIDIA’s driver from Dell website for the second time, and this time I checked the box which does a clean install, and finally the issue was gone.

Tips:

• As I mentioned, windows itself doesn’t know what’s going on, even after installing the proper driver the right way. You need to use NVIDIA control panel to change the settings, and not the windows control panel.
• NVIDIA driver does the cloning, and it runs in windows. So do not expect cloning to happen before windows boots (in POST for instance)
• I didn’t update the BIOS.
• The original NVIDIA control panel version installed on the laptop was 7.x (according to the ‘About’ dialog box under ‘Help’ menu). The driver version listed under Dell’s website was 8.x. After downloading the setup file, the file properties in the windows explorer showed version 1.x. During the installation the NVIDIA driver version was shown as 2xx. And finally after installation, the ‘About’ dialog box of NVIDIA control panel showed 3.x!