I'm experiencing a strange behavior of the vibration alert on my n900. When the screen is locked the vibration randomly weakens or is interrupted as if the vibration motor was not properly connected.

Interestingly this only happens if the screen is locked, otherwise works perfectly.

You can try it out by typing in xterm:

sleep 6;dbus-send --system --type=method_call --dest=com.nokia.mce /com/nokia/mce/request com.nokia.mce.request.req_vibrator_pattern_activat e string:PatternIncomingMessage

then go and lock your screen. after 6 secons it will vibrate as if it had received an sms. You might need to try this several times, but for me both "beeps" are seldom uninterrupted.

Is anybody experiencing a similar behavior or knows a workaround?

Maybe related to https://bugs.maemo.org/show_bug.cgi?id=7331 ? Feel free to post your observations there too if you think it's related.