Currently, the SyncComputeBracketValues function in Xext/sync.c calculates bracket values incorrectly when startOver = FALSE. A patch to fix this will be included below.

Reproduction recipe:
  1. Setup a positive transition alarm for when idle time exceeds 2000ms
  2. Setup a positive transition alarm for when idle time exceeds 5000ms
  3. Become idle, and wait for the alarms to trigger.

Expected result:
  - When idle time exceeds 2000ms, the first alarm triggers.
  - When idle time exceeds 5000ms, the second alarm triggers.

Actual result:
  - When idle time exceeds 2000ms, the first alarm triggers.
  - When idle time exceeds 5000ms, the second alarm does not trigger.

Analysis:

 1) When you first setup the alarms, the SyncComputeBracketValues function is called with startOver = TRUE. In this case, the bracket values are calculated correctly, and the member variable "bracket_greater" on the idle time counter is set to 2000.
 2) When the first alarm triggers, the SyncComputeBracketValues function is called with startOver = FALSE, from SyncChangeCounter. In this case, the second alarm should be set up, and the member variable "bracket_greater" on the idle time counter should be set to 5000. However, because the test value (5000) is greater than the previous value of bracket_greater (2000), this alarm is not enabled.

Solution:

To fix this problem, I updated the SyncChangeCounter function to call SyncComputeBracketValues with startOver = TRUE. This causes "bracket_greater" to be reset and the alarm to be triggered correctly. After doing this, the startOver variable is always set to TRUE, so I also cleaned up the code and eliminated this parameter altogether.