# [UNFIXABLE] No mouse. PS/2 Y-connector.

## zolxd

Generic PS/2 mouse and keyboard share a single PS/2 port via Y-connector.

The mouse is fine on another system with separate PS/2 ports.

I can't find any hint that the mouse is being detected at all.

And udevadm doesn't seem to have a 'look harder' option.

Nothing unaccounted for in /proc/bus/input/devices, matching /dev/input (of course).

Ditto /sys/devices/platform/i8042/serio0

Is there any way I can help it find a second device on serio0 ?

using udev-149, baselayout-1.12.13.

(openrc is masked, and init.d/udev and udevmount require baselayout-2)Last edited by zolxd on Thu Jun 24, 2010 10:09 pm; edited 1 time in total

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## BradN

I don't think linux supports two devices on one port like that, or if it does, it may need a bus mouse option turned on.  I think a simple Y adapter will lead to collisions on the wire that may make it difficult to type (the only data protection guaranteed in use is parity, but some devices may be smarter) - I think a proper bus mouse implementation uses a more active splitting so that messages from one can be delayed until the other finishes sending.

Interesting side note... even a standard keyboard by itself is prone to bus collisions if the PC decides to change the active LEDs at the same time a key is pressed.

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## zolxd

That was my original assumption, but an experienced builder suggested it as the simplest solution, so I've been working under the assumption that it must work for Windows at least, so there must be a way under Linux.

I've spent about a week on this with no progress.

Very hard to glean anything useful about it from the internet, but it seems that, at best, such functionality is motherboard/bios specific, and typically restricted to laptops. (If it really exists)

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