Duplicate edge-triggered interrupt after priority re-arbitration.
Description:
There is an occurrence of duplicate interrupt when an edge-triggered interrupt higher in priority comes closely to any other enabled interrupts. The following
is the sequence of events that leads to the duplicate edge-triggered interrupt::
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•
•
•
•
1. An active interrupt is waiting for acknowledgement
2. An edge-triggered interrupt of higher priority triggers closely to the lower priority interrupt just when it is acknowledged
3. The higher priority edge-triggered interrupt supersedes and fires a new interrupt to the core
4. The core acknowledges the higher priority interrupt without clearing the pending state and finishes the interrupt service routine with EOI
5. A duplicate of the higher priority edge-triggered interrupt is triggered because of the uncleared pending state
Impact:
Enabling any edge-triggered interrupts higher in priority than other enabled interrupts may lead to the duplicate edge-triggered interrupt. This includes
edge-triggered IRQs, global timers and IPI.
Workaround:
Chose one of the following workarounds based on the interrupt type:
• Configure the higher priority interrupts as level-sensitive only
a. In case of IRQs this can be configured in the Vector/Priority Register.
b. It is not an option for global timers or IPI.
• Any enabled edge-triggered interrupts must be no higher in priority than the other enabled interrupts.
Resolution:
No plan to fix
TM
2
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