Booting will not finish with Apple Cinema Display 20" connected

[jomatthe]

Hi All!

On previous builds I've used this monitor without any issues when it was connected to a PCI-E discrete video card. Recently switched to using on board video and now my machine won't finish booting with the cinema display (DVI) connected.

Never had any issues with my UEFI sierra installations (been following Tonymac guides since Mountain Lion) and the current build (without graphics card installed) has zero issues with a different monitor connected (Samsung LCD TV via DVI). Same results using hdmi to DVI adapter to ACD.

System: Gigabyte Z77n-wifi/i5
BIOS settings: optimized defaults plus disabled virtualization and serial port. Graphics set to AUTO.

When booted with Apple cinema display connected, verbose readout stops after a bunch of ACPI related lines. ( could post a pic if needed).

I read the only ACD thread on here about the USB hub potentially causing a problem so never plug it in either.

Any ideas where to begin fixing this?

 

[jomatthe]

Tried dual display with LCD plugged into HDMI and ACD plugged into dvi, no go. With LCD into DVI and ACD into HDMI, got dual display!

Upon reboot, ACD showed bios post screen at proper resolution. Tried rebooting with LCD powered off, worked again same way (finished booting properly).

Tried rebooting with LCD unplugged (ACD still in HDMI), BIOS Post screen showed at scaled resolution and same boot freeze part way.

For now going to try just leaving LCD plugged in (powered off), but I am still baffled by this strange issue!

 

[jomatthe]

Abandoned this cause as this system is now connected to a new monitor which works normally with the onboard gfx. Going to blame the ACD for this one.