Ubuntu kernel > 4.4.0-51 reboots w/VGA connection
Short version: All kernels after 4.4.0-51 reboot almost immediately when running with a VGA cable. Earlier kernels are all fine. Changing the monitor cable from VGA to a DVI cable (on the same monitor) solved the problem. Why? Is this a feature or bug or ???
I have an MSI motherboard, A78M-E45 (MS-7721) and a Dell 20" LCD monitor which until today has always been connected with a VGA cable. The motherboard & monitor both support DVI connections but I had used a VGA cable on an even older monitor that only supported VGA and I was just lazy and kept using the same cable even with the Dell monitor.
For years the system has been running just fine with many past versions of Ubuntu & kernel. With Ubuntu 16.04 (current/
After kernel 4.4.0-51, each subsequent kernel (4.4.0-57, 4.4.0-59, and now 4.4.0-62) I installed through the standard distribution would almost immediately reboot. I did not get any kern.log or even syslog information so I was at a complete loss to figure it out.
With each of those later kernels that would reboot, I was able to use grub and select the recovery mode of each & every kernel with no problem, and then continue the boot process. The monitor was always locked in a 1024x768 resolution even thought it's native resolution is 1600x1200 but I assumed that was just a function of recovery mode. Finally today I thought I'd try using a DVI cable instead. Immediately every kernel started booting normally without any problems, not requiring recovery mode.
I'm happy that I can now boot normally with the more recent kernels, but I'm at a loss to explain why a VGA cable wouldn't work on the most recent kernels. Perhaps there is some issue with EDID over a VGA cable, but does anyone know enough of what changed after kernel 4.4.0-51 that would cause this, and is there some setting I might change that would allow me to continue to use a VGA cable? I have no issue running with a DVI cable forever, but I'm just bothered that something else is wrong that may come back to haunt me later.
I still have all the kernels mentioned above installed so I can easily use grub to select a different one for testing any theories.
Thanks in advance.
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