Man, just read this thread for the first time from start to finish, I need to ask for clarification from the OP.
The problem, when setup for multi-display 4k - display port and other to HDMI, on a reboot or immediate cold start, the secondary display (4k due to port priority) goes black (the TV recognizes signal but fails to display) and stays black even after you boot into windows?
Is the only way you can correct this to do a shutdown, wait a few minutes and cold boot again?
Yes, only cold boot after power off for at least half a minute can w7 be sucessfully booted in with both screens turned on normally.
Please read the following post for further clarity.
Again, today, I received the following email from nVidia as follows:
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Hello Stuart,
Thank you for the update.
It depends on card to card as to what port is set as the primary one and hence that port takes over the primary BIOS or the Boot screen.
With regards to the black out, if you are referring to the Blackout during the reboot or a system start, then its normal for only one screen to stay on.
If the blackout is happening in the windows, I kindly request you to provide us more details on the issue and we will be more than happy to help you fix it.
Regards,
Vaseem
NVIDIA Customer Care
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and my reply
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Motherboard : Gigabyte GA-Z77-D3H v1.0 with F22 uefi bios
Graphic card: evga 750 Ti FTW
Dual screen config: Asus PB287Q 4k monitor and connected to the Display Port as my main display. Another 40" LG LCD panel (1920x1080) connected to HDMI as my extended display.
Cold boot w7 is usually successful to have both screens turned on normally after power off for more than half a minute.
However, warm boot, i.e. restarting w7 from Windows, always lead to the Asus screen black out and the sequence is as follow:
1. Mouse click the Start button and select Restart, w7 begins to shut down. After a numbers of seconds, W7 is completely shut down with both screen turn off due to no video signals.
2. After a few seconds, the Bios Boot screen appears on the HDMI (LG 40") screen.
3. Again, after a further few seconds, the w7 boot screen appears on the HDMI screen, followed by the Asus screen power indicator light changing from yellow to white, indicating it is receiving video signal from the Display Port. However, the Asus screen remains totally black.
4. After further few seconds, w7 is completely kicked in. The LG extended screen shows the normal w7 wallpaper, while the Asus main screen remains totally black.
In short, cold boot w7 after at least half a minute power off can boot w7 successfully, while warm w7 from Windows always end up with a black out Asus main screen.
I have suspected the problem may due to the Display Port connection, so I ran the following tests:
1. Disconnect the HDMI screen, leaving the Asus screen alone connected to the Display Port.
Bios Boot Screen appears on the Asus screen and w7 can be warm or cold booted normally. Seems like 750Ti can support a single screen connection to the Display Port without any problem.
2. Connect the Asus 4K screen to DVI instead of the Display Port:
The Asus screen has two HDMI and one Display Port. In order to connect the Asus main screen to the 750Ti DVI, I bought a DVI to HDMI cable for the purpose. The LG 40" is connected to HDMI. Bios Boot Screen appears on the Asus screen and w7 can be warm or cold booted normally.
So, the problem seems to be narrowed down to the Display Port connection in a multi-screen setup.
I hope these will help you dissect the problem and please let me know if you need info or to run further tests from my end.
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It seems nVidia remained shy away to call the black out Asus screen a problem, but I see their attitude changing. They are willing to look into the problem.
Stay tune, I will come back when I receive anything new from nVidia.
Roy
