Comment 1 for bug 127868

I saw the same bug on 32bit x86, gnome-power-manager (2.19.5-0ubuntu1 from gutsy) wasting 1-10% of CPU. Strace was very similar:

....
[pid 27866] ioctl(21, 0x4122, 0xb4b6ff88) = 0
[pid 27866] ioctl(21, 0x4122, 0xb4b6fe80) = 0
[pid 27866] read(20, "\1\0\0\0\361\37\247F\372%|4\1\0\0\0", 64) = 16
[pid 27866] ioctl(21, 0x4122, 0x824bc40) = 0
[pid 27866] ioctl(21, 0x4122, 0xb4b700b8) = 0
[pid 27866] ioctl(21, 0x4122, 0x1800) = 0
[pid 27866] poll([{fd=20, events=POLLIN|POLLERR|POLLNVAL, revents=POLLIN}], 1, -1) = 1
[pid 27866] ioctl(21, 0x4122, 0xb4b70068) = 0
[pid 27866] ioctl(21, 0x4122, 0x400) = 0
[pid 27866] ioctl(21, 0x4122, 0xb4b6ffe8) = 0
[pid 27866] ioctl(21, 0x4122, 0xb4b70138) = 0
[pid 27866] ioctl(21, 0x4122, 0xb4b70088) = 0
[pid 27866] ioctl(21, 0x4122, 0xb4b70068) = 0
[pid 27866] ioctl(21, 0x4122, 0xb4b70048) = 0
[pid 27866] ioctl(21, 0x4122, 0xb4b6ff88) = 0
[pid 27866] ioctl(21, 0x4122, 0xb4b6fe80) = 0
[pid 27866] read(20, "\1\0\0\0\361\37\247Fe\243\3015\1\0\0\0", 64) = 16
[pid 27866] ioctl(21, 0x4122, 0x824bc40) = 0
[pid 27866] ioctl(21, 0x4122, 0xb4b700b8) = 0
[pid 27866] ioctl(21, 0x4122, 0x1c00) = 0
[pid 27866] poll([{fd=20, events=POLLIN|POLLERR|POLLNVAL, revents=POLLIN}], 1, -1) = 1
[pid 27866] ioctl(21, 0x4122, 0xb4b70068) = 0
[pid 27866] ioctl(21, 0x4122, 0x400) = 0
[pid 27866] ioctl(21, 0x4122, 0xb4b6ffe8) = 0
[pid 27866] ioctl(21, 0x4122, 0xb4b70138) = 0
....

And this was spinning as fast as possible. Killing gnome-power-manager and restarting returned sanity.