There do appear to be a number of posts on this but I cannot find one that helps me address it.
I have an HP EliteBook 8470p (SN CNU3039BJW). I have searched the HP website to confirm the graphics card by the serial number is not found. The laptop is connected to a Philips 273V.
I have installed:
Linux lt-basel-a.baselmania.com 4.12.9-300.fc26.x86_64 #1 SMP Fri Aug 25 13:09:43 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux (Fedora 26)
According to the OS: Intel® Ivybridge Mobile
lshw -c video gives
description: VGA compatible controller
product: 3rd Gen Core processor Graphics Controller
vendor: Intel Corporation
physical id: 2
bus info: pci@0000:00:02.0
width: 64 bits
capabilities: msi pm vga_controller bus_master cap_list rom
configuration: driver=i915 latency=0
resources: irq:31 memory:d4000000-d43fffff memory:c0000000-cfffffff ioport:4000(size=64) memory:c0000-dffff
The external philips screen flashes off and one randomly. Further when on the recommended resolution the text is not clear with everything on that screen vibrating. If I drop resolution the text is clear and the vibration stops but the blanking out continues.
What I do find strange is that when I completed my fresh install yesterday it appeared to be working fine but now after doing a 2nd re-install it is now.