Multi-display setup in Windows 10 IoT (W21H2-1-5-2) on iMX8M PLUS EVK

[MichaelV]

Hi, I've tried many things, but I just can't get 2 HDMI monitors going at the same time on the iMX8M Plus EVK (8MPLUSLPD4-EVK) running Windows 10 IoT (using the W21H2-1-5-2-imx-windows-bsp-binaries.zip).

One HDMI monitor is connected to the HDMI port.

The other HDMI moinitor is connected to the MIPI DSI port using the iMX-MIPI-HDMI board.

If I boot the board with the HDMI monitor connected to the MIPI-DSI port (no matter if I have or don't have the other HDMI monitor connected to the HDMI port), the board boots and shows display output (the Windows logo with spinning circle) ONLY on the HDMI monitor connected to the MIPI-DSI port. However, the board then reboots, tries again, reboots again and then shows the "Preparing Automatic Repair". I can't continue on the next screen (telling me to "Choose your keyboard layout") because the USB does not work at all when the board gets into the automatic repair mode.

The only way out of this is to detach the MIPI-DSI port completely, reset the board and then Windows 10 IoT boots normal on the monitor connected to the HDMI port.

Note that USB mouse and keyboard work perfectly fine when booting Windows 10 with only the HDMI port connected.

I have tried these registry settings:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000]
    "EnableMultiMon"=dword:00000001
    "Display2Interface"=dword:00000002
    "Display2NumLanes"=dword:0000004
    "Display2ChannelId"=dword:00000000
    "Display1Interface"=dword:00000001

And I've also tried with these registry settings:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000]
    "EnableMultiMon"=dword:00000001
    "Display0Interface"=dword:00000002
    "Display0NumLanes"=dword:0000004
    "Display0ChannelId"=dword:00000000
    "Display1Interface"=dword:00000001

Inside Windows 10 IoT, the display settings show that I have two displays, set to duplicate. It appears the monitor on the HDMI port is always Display 2. When I connect the 2nd monitor on the MIPI-DSI port, nothing on that monitor comes alive (but we know the port is good because booting the board with an HDMI monitor connected to the MIPI-DSI port shows display output on that monitor, it just won't boot through).

According to this post, it should work with up to 3 monitors. I also tried with exactly the registry settings as in the Display.zip file attached to that post:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000]
    "EnableMultiMon"=dword:00000001
    "Display0Interface"=dword:00000004
    "Display0BusDataWidth"=dword:00000018
    "Display0BusMapping"=dword:00000001
    "Display2Interface"=dword:00000002
    "Display2NumLanes"=dword:0000004
    "Display2ChannelId"=dword:00000000
    "Display1Interface"=dword:00000001

but I'm getting the same results; as soon as the MIPI-DSI port has a monitor connected and I boot the board, it shows display output just on that monitor, then resets and gets to ""Preparing Automatic Repair"".

If I boot the board with just the HDMI port connected to a monitor, Windows 10 boots fine and the display options in Windows 10 show I then have Display 1 and 3 (duplicate desktop on 1 and 3). Nothing shows on the monitor when I connect it to the MIPI-DSI port (not even when I select "Show only on 1"). The display on the HDMI port is now apparently display 3 (because I can set "Show only on 3" and the output remains on the monitor on the HDMI port).

What am I doing wrong? This should be a supported scenario, right?

[danielchen]

Hi Michaelv:

Please refer to below link, for current windows 10/11 support, you can get in touch with ProSupport tam at prosupport@nxp.com

Windows 10/11 IoT Enterprise for i.MX Applications Processors | NXP Semiconductors

Regards

Daniel.

[MichaelV]

If I pay for support and this turns out to be a bug in the latest BSP release, will I get my money back?

This was apparently all working in W21H2-1-5-0, so...

It's a bit crazy NXP doesn't even supply the minimum of support. It's not like I have a deep technical question. It's simply "is this a supported scenario or not" and it would take one of your engineers less than 3 minutes to read and comment.

I think it shows how much NXP believes in Windows on ARM, but alas, can't blame you on that.