Keyboard presence not recognized at boot


Increasingly over time, i.e., days I experience that the keyboard (and mouse) is not recognized when booting. Now it’s every time I boot. However, there is a fix. If I plug out, and immedeatly plug in again the keyboard connector everything is fine, except that keyboard short cuts not always work depending on application. In the mouse case the right mouse button doesn’t respond either. Besides these effects the system, openSuSE 11.3, boots fine.

It’s a hazzle everytime to plug in and out again. I’m opting for another fix.

Nothing suspicious in /var/log/messages.
I’ve tried to see if there is a particular led light sequence on “num lock”, “Caps lock”, “Scroll lock” that I can get som info from, but I haven’t been successful.

Anyone got a suggestion to what might be the cause of this behavior?

Keyboard is kwd-205
Mouse is Microsoft wheel optical mouse
Base Board Information
Product Name: NF7-S/NF7-M/NF7 (nVidia-nForce2)
Version: 1.X
Serial Number:
BIOS Information
Vendor: Phoenix Technologies, LTD
Version: 6.00 PG
Release Date: 09/10/2004


I assume this is not through a hardware KVM switch.

If you switch off the PC (from the switch on the back), unplug it from the wall, plug back into the wall, switch on the PC on the back, and then switch ON at the front so that it boots, what happens ?

(I’m looking for a hardware capacitive effect, possibly caused by bad grounding, possibly caused by a bad design).

Please confirm the PC plug to the wall is a 3-pronged plug.

Every single time I had a problem with kbd or mouse malfunctioning it was a always a hardware issue, ranging from bad usb (front panel) connector to failing mouse to partially-functioning keyboards to broken cords. I’ve used corded and wireless mouses and kbs, as well as wireless usb and/or ps2 kbd+mouse combos.

It’s very unusual not to get at least the basic kbd functions at boot time, since this is managed by the BIOS, so I’d test if it’s something that is happening after the OS kbd/mouse driver takes over by booting to the bios a number of times, under different times off (cold or warm hardware) and see if I can use the kbd in it.

If it’s ok in BIOS but fails intermittently after X takes over, check dmesg for usb-related errors (if your mouse/kbd are usb, of course). You may see a hardware error message, indicating failed hardware.

And once I thought a wireless mouse has failed (erratic) but I only had to replace the batteries…


I did as “oldcpu” suggested. No change. Still no keyboard o present during boot. Thus, I’m unable to enter e.g. BIOS settings. BTW, keyboard is plugged to the PC with a PS/2-connector.Mouse is connected with a USB->PS/2 adapter, so both devices are wired. No grounding effect has ever been noted.
I thought about repacing kbd and mouse, however, they work both after re-(hot)plugging the kbd. So I guess they are alright.
From dmseg I obly get tons of messages that starts with “SFW2-OUT-ERROR” or “SFW2-INext-DROP-DEFLT”. Annoying.
Still no suspicious error messages in /var/log/messages.

Might it bee something with motherboard? Battery?

I remember from the old old days when the plugs changed from DIN to PS/2, that there were many warnings against hot-plugging anything in a PS/2 port, under risk of frying the controller circuit or even the motherboard. And this kind of damage accumulates, you know, until the circuit in question stops working. You should ALWAYS connect/disconnect with the computer off. PS/2 is NOT hot-pluggable as USB nor e-SATA.

If I where you I’d test with another kbd, perhaps an USB one, as the problem may rest with the onboard PS/2 socket/circuit.

BTW, solved this one be replacing the power supply. Apparently it was about to shut down completely, and replacing it turned out “miraculously” to exterminate the erratic keyboard behavior as well.

Thanx to all though for input and insight.

Thanks. Most educational (thats a new failing power supply symtom for me to learn).