Comment 14 for bug 1238410

Revision history for this message
In , Peter Hutterer (peter-hutterer) wrote :

An XSync alarm on the IDLETIME counter set up for a negative transition may not trigger. Specifically:

- the alarm is set up for NegativeTransition, delta 0, abs value 10ms
- if the idle time is > 10ms, a move of the mouse resets the idle time counter to 0. This will trigger the alarm notify to be sent (correct behaviour)
- SyncComputeBracketValues() is called to re-compute the bracket values
- the bracket value for the negative transition (10) is higher than the current value (0). Thus, the bracket is not set.
- the idle timer goes above 10 ms, but a reset will _not_ send an event from now on.

However, if after the 10 ms any alarm triggers and/or is changed by a client, SyncComputeBracketValues() will recompute the bracket values and will install our alarm as lower bracket. Thus, it will trigger for the next reset.