Scott Wood writes:
This patch causes a sync do be done after masking a QE interrupt, to
ensure that the masking has completed before interrupts are enabled.
This allows the masking of the cascade IRQ to be removed without causing
spurious interrupts.
Hmmm. In general a sync having completed doesn't mean that previous
MMIO stores have actually got to the device. Reading from a device
register generally does ensure that previous writes have actually got
to the device though - could you do that instead? I'm concerned that
adding the sync is not a robust fix and is possibly only working due
to fortuitous timing.
Paul.