My W510 was working fine on Windows 8. After updating to Winodws 8.1 (Prior installation, the 3.01w8x86 driver has been installed, and downloaded & installed update Windows 8.1 from Microsoft Store), there are a few issues.
1. Sleep button on the Top right corner not working. W510 cannot go into sleep mode with the physical sleep button.
2. Pressing Fn + F4 cannot goes into sleep mode.
3. After plugging in the keyboard dock, the W510 would turn off the screen only after closing the lid, it does not go into sleep. When I re-open the screen, it does not go into Windows Lock screen, it goes back to where I left.
The only way to go into sleep mode:
1. Press Win key + I, Go to Settings -> Power-> Sleep
1. I can wake the tablet up using the sleep button after the W510 has gone into sleep mode
2. All the other function keys work. Fn+F3 would go into Flight mode, Fn + F8 would mute speaker.