I've upgraded 8 computers to 11.04 from 10.10 through the standard update version process. Two are giving me problems with the UDB optical mouse being frozen upon boot, to either a login prompt, or to the desktop.
Both computers are running AMD processors. Both are 32 bit systems. One has nVidia graphics and one has ATI graphics, which seems to rule out graphics. I tried changing the drivers on the nVidia system and that didn't make any difference. Doing a complete power down of the system was the only way I found try to get it working until I discovered that if I unplug the mouse mouse and plug it back in, it will work fine from then on. Doing a restart when it is frozen never results in a functioning mouse. Other than unplugging the mouse, a complete power down is required.
Both systems were using the same make/model of mouse, Logitech. To rule out it being the mouse, I've been using one of them on my laptop with 32 bit Ubuntu 11.04, and it has worked perfectly, so it most likely isn't a mouse issue, although using an Acer mouse on the one system seemed to alleviate the problem.
If I plug the Logitech mouse into the front mouse USB ports instead of using the rear USB ports on each computer, the number of times the mouse is frozen on boot has significantly been reduced. It still happens occasionally, but not nearly as frequently. Both computers are using PS2 keyboards, so I don't know the situation would be if they were USB.
The computer with the ATI graphics card is my wifes. I have the exact same computer at home with nVidia graphics at home. Mine has worked perfectly. But the other computer with problems has nVidia graphics, so, as I said before, I doubt it is a graphics problem.
I'm guessing it is a kernel issue.
One suggestion I found on line was modifying the grub file line
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash pcie_aspm=off"
but that didn't make any difference. Both machines worked fine in 10.10, 10.04, 9.10, and 9.04.
It has now been two weeks since the last update here. My co-worker purchased a new Logitech wireless mouse. There have not been any freezes on boot with the wireless sending unit on either a front or rear USB port. On my wife's computer about 20% of the time her mouse is frozen on boot, but unplugging it and replugging it makes it work without issue.