I just tested the linked upstream kernel. It does not change the behavior, I am observing the same bug on v4.1-rc8-unstable.
I added the tag accordingly.
Regarding the question whether this was happening after an upgrade.
Well it's actually a little complicated.
If my memory does not deceive me, I did not observe this problem when I installed Ubuntu 12.04 on this laptop in 2012.
Some time afterwards, after an update this problem occurred.
Unfortunately at the time I was otherwise occupied so I just attached the mouse to the USB 3.0 port and did not report the bug.
And by the time my schedule had cleared up a bit I had forgotten all about the problem, until I recently switched USB ports with the mouse and stumbled upon it again.
So it is probably a regression albeit only compared to a three year old kernel.
I will try testing the 12.04.X releases and see if I can actually find a reliably good version, and then maybe start bisecting from there, though this may take some time.
If some other debugging information would be useful let me know.
I just tested the linked upstream kernel. It does not change the behavior, I am observing the same bug on v4.1-rc8-unstable.
I added the tag accordingly.
Regarding the question whether this was happening after an upgrade.
Well it's actually a little complicated.
If my memory does not deceive me, I did not observe this problem when I installed Ubuntu 12.04 on this laptop in 2012.
Some time afterwards, after an update this problem occurred.
Unfortunately at the time I was otherwise occupied so I just attached the mouse to the USB 3.0 port and did not report the bug.
And by the time my schedule had cleared up a bit I had forgotten all about the problem, until I recently switched USB ports with the mouse and stumbled upon it again.
So it is probably a regression albeit only compared to a three year old kernel.
I will try testing the 12.04.X releases and see if I can actually find a reliably good version, and then maybe start bisecting from there, though this may take some time.
If some other debugging information would be useful let me know.