On Fri, Aug 18, 2023 at 07:58:03PM +0200, Karel Lucas wrote: > > Dear Nick, > > For more than ten years I have been working with an ATEN brand KVM switch > together with several computers, including linux and openBSD (version 4.1). > In all these years I have had no problems, not with my KVM switch, nor with > any degree of disconnection. The keyboard works flawlessly via the switch, > it's only the mouse that I have a problem with, and only with openBSD. >
This is not very clear at all. You have used the same KVM switch for ten years, but haven't considered it having hardware degradation over that time? Capacitors are well known for having limited lifetimes and are *usually* the first item looked at in repairs. Switches also fail due to dirty contacts. Or, are you saying that everything worked fine for OpenBSD 4.1, but not for OpenBSD 7.3? The changes over that time have been enormous. > Op 17-08-2023 om 13:56 schreef Nick Holland: > > > > First of all, does your mouse work directly plugged into the OpenBSD > > computer? > Yes, it does. > > If so, it's your KVM switch. > As I mentioned above I have been working with my KVM switch and openBSD for > over ten years with very good results. > > > Second...if you boot the OpenBSD machine with the KVM pointed at the > > OpenBSD machine, does it work? > No, even then it won't work. Have you swapped ports on the KVM switch to rule out a partial hardware failure on the switch? Have you also disconnected the other hardware and OS inputs to rule out them as the source of the problem? Have you checked that the other machines are producing the correct supply voltages? Power supply failures are a consistent problem with computers. High or low voltages don't mix well. Have you checked with your switch manufacturer to make sure there wasn't a problem with your switches model? It happens a lot. After ten years of service, if you insist that the switch isn't the problem, (Prove it) then you need to also prove that the other hardware is functioning properly. Do not believe what the BIOS or sensors say that the voltage is. A bad voltage will cause those readings to fail. Get a good voltmeter with excellent probes for this kind of work and check *everything*. Please use a great deal of care. You will need to measure voltages on the motherboards in addition to what the power supply puts out. Everything is running and you will need to check in many spots. Also, there are high voltages inside the power supply. Don't get electrocuted. Drain the voltages off the capacitors in there with a suitable tool for that purpose if you go inside there. Yes, even with the power off and power cable disconnected. And it's tricky. I have a power supply cable for two hard drives. Two connectors crimped across the same cable. One of the crimps is bad. Recognizing that saved me a trip to hell after about an hour. Easy to fix, damned hard to locate. Chris Bennett > > You > > might be able to improve how OpenBSD deals with KVM switched mice, > > because yes, it does seem to be a little more touchy than some other > > OSs, but someone with good programming and HW trouble shooting > > skills AND a cheap-*** POS KVM switch would have to care. Most people > > that skilled generally just buy a better KVM switch and move on. > That more than ten years of loyal service proves that my KVM is of good > quality. > > What does the dmesg show as you switch the KVM around? That would tell > > us how the KVM works. Some are equiv. of plugging and unplugging the > > mouse/keyboard/monitor, some do some kind of "keep alive" so the > > computer thinks the mouse is still there. Both can cause problems of > > different types (my "good" one seems to plug/unplug the mouse/keyboard, > > but has a great keep-alive for the monitor). > What I've learned about my KVM switch over the past ten years is that both > the mouse and keyboard are emulated when they are switched to another > computer. Never have I had any problems with my computers when switching > with my KVM switch. > > >
