USB Anomaly with dual-boot (7/10) ASUS Sabertooth Z170 S

[BonzaiDuck]

I should probably continue forward to hunt this down at the ASUS forum or website. Perhaps I should even post the following at the forum there, too.

This is not the sort of problem even the modest enthusiast may experience.

I recently replaced 20+-year-old PS/2 KVM switch with a 4K-capable, DVI/USB switch. I favored the DVI connection because it insures 144Hz refresh instead of 60. Whatever I do for my latest system must also integrate with the older ones.

So -- I regret now -- that I purchased this Emerson/Avocent DVI/USB KVM which allows for all of that. I was first unhappy that it wasn't HDCP compliant, when straight-through DVI-to-DVI is guaranteed to be. Luckily, my monitor also acts as the "V" part of a KVM. So I have to use both hands when switching.

With the Skylake system, the KVM was connected to one of the USB2 ports at the narrow top of the I/O plate. When I would boot into Windows 7, I could always count on the keyboard and mouse to be functional at boot time.

But when any of the following needed to occur or just happened to do so:

== Switching restarts between OSes
== [Other, non-USB] driver changes in Win 10
== BSODs - which I can still count using two hands for the time since I first put this system together

then, the keyboard connected to the KVM and the mouse as well come functional at the boot menu (selecting 7 versus 10), and then fail to function at the logon screen.

Plugging a second keyboard -- mine is PS/2 through PS/2-to-USB adapter -- I can restart the system again, even though the mouse will not function until I similarly swap it to a direct PC connection or plug in a handy wireless mouse.

Usually, this would sort itself out. Maybe I would enter BIOS just to inspect the settings, puzzled about the HID problem.

I am currently experimenting at the moment with the KVM-to-PC connected to the PC's USB 3.0 port at the I/O plate.

After I made the switch -- leaving the system in its win desktop status and switching to another computer system so I could re-deploy the USB plug at the I/O plate -- it all seems fine.

ASUS had needed to publish a utility for slipstreaming a USB3 driver to Windows 7, or it would not continue the install process from the original disc. I have read here or elsewhere that the USB2 ports of the motherboard are really controlled by the USB3 controller.

HAS ANYONE ELSE EXPERIENCED SIMILAR PROBLEMS -- WITH DUAL-BOOT? WITHOUT DUAL-BOOT? WITH KVM SWITCH? WITHOUT KVM SWITCH?

WHAT WAS YOUR EXPERIENCE IN RESOLVING THE PROBLEM?

My troubleshooting continues, and I may come back with more observations.

UPDATE: Using the USB3 port seemed to have resolved occurrence of the problem when OS-switchover Restarts occur. I don't think this happens with Windows 7, or I would not have gone so far with this dual-boot setup. Now -- what happens with an IRST driver reinstall or something else, have to wait and see. . . .

 

[lopri]

I am a little confused by the description. Since this is a KVM issue I assume you are using two physically separate systems, but then you talk about boot menu to choose Win7/10 which sounds like a single system with multiple OSes. Does the 2nd machine matter at all in the trouble scenario you are describing?

Since your issue disappears with a USB3 port, there are two possibilities:

1) Power: Is your KVM bus-powered or powered externally? If it is bus-powered, check the USB Hubs in Device Manager. Try changing power-related options. Uncheck to disallow the device from falling asleep.

2) Drivers: Intel's USB 1.1 is proprietary (UHCI) and does not conform to the open standard (OHCI) . Devices designed to work with OHCI may fail to fall back on Intel's UHCI in USB 2.0. I have learned about this when I found out my PS3 joystick does not work with Intel chipsets. A workaround at the time was to use a PCI card based on VIA chipset. USB 3.0 does not suffer the same issue as you noted. In your case, it is possible your KVM works around the backward compatibility issue in Windows by its own drivers, which the OS fails to load when something unexpected happens.

Hope your issue is resolved soon. I understand how frustrating a minor problem like this can be.

 

[BonzaiDuck]

OK. Z170 motherboard, latest BIOS. Dual-boot system, connected to KVM sharing keyboard/Mouse/video between 3 systems. No other systems have been a problem. But switching OSes in the former would occasionally exhibit this problem, which makes for an inconvenience.

As I said, there would always be such issues to sort out if the system suffered a BSOD or instability, but the system is stable under either OS. For a new enthusiast-built system of just over four months' running, the resets had occurred mostly during the first two days of "tuning." I can almost explain in detail what caused a reset/BSOD or instability since then, but there are no such problems now. Instead, the anomaly may occur after the dual-boot menu when I actually changed the OS being used.

However, connecting my KVM to the dual-boot-system's USB3 port (as opposed to the USB2's) seems to have made the trouble go away. Let's say the sample of events to confirm even that is a bit sparse, but I've rebooted and changed OSes a few times and no problem.