Hello!
I’m new to this forum, and relatively noob with Linux. I have dual boot Fedora 42 with Windows 11 on my secondary PC. After the latest big upgrade i cannot use my Keyboard or mouse through KVM switch anymore. The screen is working tho… Everything works fine in the grub, in Windows, on another computers, just not with linux. I will repeat myself, but before the update the switch worked in Fedora too. I repeated the installation of Fedora on my tercial PC, did updates, and the KVM works on there too. Now, i know i can reinstall linux, and hopefully it would work again, but if there is another solution, i would like to learn. If anyone know what’s happening, or has a workaround, please share it with me. Thank You all for reading my topic
I cannot assist with the KVM problem considering the dearth of information provided.
However, you should understand that with linux there are hundreds or thousands of developers with just as many different architectures and providers of hardware so hitting a target that works with every piece of hardware is like shooting darts in the dark. Most things work but a few occasionally break. Linux developers are doing the task voluntarily and unpaid for their efforts.
Microsoft has a single development team working directly with hardware providers, and they work in concert and are paid to ensure that windows works with every platform that is distributed with windows pre-installed.
Drivers change and most linux developers do not have all the available hardware with which to test things. Kernel changes require driver changes. Hardware changes require driver changes. Linux is a constantly moving / evolving ecosystem so at time the users encounter problems.
If you really want assistance then we need more detail about hardware involved, software involved, etc.
A good start would be uname -r, inxi -Fzxx, and lspci. Post the output of all those commands as preformatted text (highlight the pasted text then click the </> button on the text entry screen) or paste it like this
I think there are a few diagnostic steps that you can take before reinstalling:
- What happens if you plug your peripherals (keyboard/mouse) directly into the computer?
- Do keyboard and mouse work via the KVM switch in a live environment?
- What do you see when you run
lsusbin the terminal? Does it show the KVM switch/your keyboard/mouse? (You probably need another keyobard/mouse plugged in for this.) - Does anything stand out when you run
sudo dmesg | grep -i usb?
What’s a “tercial” PC? Is that another machine, connected to another port of the same KVM? Or did you move cables from one machine to another?
Thank You for Your answer, sir!
I understand the hard work of the Linux community, i admire their knowledge. It wasn’t my intention to offend anybody or to prove any superiority of Windows over Linux. My first encounters with Fedora was pleasant, that is why i started to put more time in to learn it. I thought, if i stuck somewhere, the forum will help me out. As a computer hardware technician it was a good idea to learn and understand Linux more than just install it, and to use basic, preinstalled programs. My first lesson today was that asking for help, without detailed informations is not a good idea. Since i didn’t knew about those command line commands i came here unprepared, and i’m sorry for that.
Thank You for Your answer, sir!
I used Your command dmesg… and noticed some messages that might get us closer to the solution, but let me first answer Your previous questions.
If i plug keyboard and mouse directly to the computer’s usb ports, they are working fine.
I didn’t try live environment yet, but as i mentioned, it worked with the same Fedora 42 system on a different computer - maybe irrelevant for this case. The next step is that i will try the LE.
The lsusb command shows my logitech mouse and the keyboard as present that are connected to the KVM switch
The message i can see in dmesg is:
usb 1-1.3: Manufacturer: Logitech
usb 1-1.3: Not enough bandwith for new device state.
usb 1-1.3: can’t set config #1, error -28
oh, it means third pc… my english is not so good.
OK, so somehow having keyboard and mouse connected to the KVM switch and then to the PC runs into a bandwidth problem.
Can you try connecting the KVM switch to another port? Or try another cable?
Probably worth to get another data point. But frankly after what you saw in the kernel log (dmesg) I do not expect a different outcome, since it is still the same system, USB port, and cable.
Ah, no worries. I just didn’t understand and didn’t just want to assume what it means. I don’t think the fact that it works on a third PC helps us all that much, apart from confirming that the keyboard, mouse, and KVM all work. But by going to another PC, you change so many variables, the mainboard, USB controller, cable, etc., which makes it hard to control for potential error sources.
The live environment will have an older kernel version, which might be another interesting variable here.
In grub i can choose older kernel, and already tried (i upgraded from 41 to 42), but didn’t help. Although, changing from USB3 to USB2 did the job. I don’t really know why, before the update it worked in USB3, but it really doesn’t matter, i can work now as before. Thank You for Your help, as a technician i could’ve thought of it, it just sounded illogical, because on the hardware side i didn’t change anything, and to be more confusing, windows worked without issues. When USB3 was first introduced, i avoided it to use for mouse/keyboard, because it had some issues, but over the years, i forgot about it. Than You sir, for your help, i learned a lesson: sometimes the easiest and most illogical operation will solve your problem 
USB is a complex beast, with OHCI (USB 1.1), EHCI (USB 2.0), and XHCI (USB 3.0). This kind of sounds like there might be an issue with XHCI on your system/kernel combination. You could see if sudo dmesg | grep -i HCI turns up anything interesting. Also, most UEFI implementations have a setting called “XHCI handoff”, which controls whether your OS handles USB 3.0 (when set to “on”) or your BIOS does (when set to “off”). On modern OSs, I would always recommend setting it to “on”. But this could explain the different behavior of Windows and Linux.
Well, as someone who has spent a fair share of time debugging other people’s PC issues (and my own), my first assumption is always that a user saying “it just happened, I didn’t change anything” has in fact changed something and simply forgotten about it. Recently, I debugged an issue I had run into a year ago, solved then, and now reintroduced again because I have the memory of a goldfish.
Well, you may be right i don’t want to argue with you, since You helped me solving my problem. It’s embarrassing, beginners mistake, but things happen. At least, this was a semi-legit reason i registered to this forum. One day, maybe, i will be able to help people here, so i can encourage others to use linux, just like you, guys did today. thank you again
I wasn’t trying to argue, I only wanted to explain why I ignored your statement that nothing changed but a software update and started to go into hardware debugging mode first. And truth be told, I did pause for a moment when I read your statement that everything worked in Windows (with all the same ports, cables, etc. involved).
Nothing to be embarrased about. Something did change on your system which caused your keyboard and mouse to stop working. And while we don’t know what it was, I am glad your system is working again.
I experience this from time to time on my Levovo Thinkpad P51 (working through a Lenovo docking station and a TESmart KVM switch. As a matter of a fact it started happening again after recent updates (I think around the time of of kernel release for 6.17.7-200 (although I am not saying it is related to the kernel update)). I find that it happens after waking from sleep mode. I can get the mouse/keyboard working again by the following steps in this order: 1) power off/on TESmart KVM. 2) unplug/replug USB cables for mouse and keyboard from/to TESmart KVM.
In addition there seems to be a time factor involved with the unplugging/replugging of the mouse/keyboard cables from the TESmart kvm. If the time lapse between the unplugging and replugging of the cables is not long enough then the mouse and keyboard will not get reinitialized and become active.
Running the lsusb command before the mouse/keyboard is working and then again after the mouse/keyboard is working indicates the following USB devices are missing from the list before the reset and are present after the reset:
Bus 001 Device 013: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 014: ID 0c45:7403 Microdia Foot Switch
I assume these indicate chipsets used by the TESmart kvm.