[PATCH] qe_ic: Do a sync when masking interrupts.
scottwood at freescale.com
Tue Oct 24 04:22:57 EST 2006
Kumar Gala wrote:
> On Oct 23, 2006, at 10:19 AM, Scott Wood wrote:
>> Possibly -- but the only problem on the rare occasions where the timing
>> is not fortuitous is a spurious interrupt; the only reason the sync
>> needs to be there at all is to avoid the overhead of the extra interrupt
>> (and to avoid user complaints that they're getting "BAD" interrupts).
> Why wouldn't the read accomplish the same thing in a more robust way
> than the sync?
It would. However, it also adds a small amount of overhead to every QE
interrupt, and the only thing that that overhead buys is avoiding
possible but empirically very rare spurious interrupts; it'd cost more
than simply accepting that a spurious interrupt might happen once in a
Without any type of sync, spurious interrupts happen fairly regularly
(about 5-10% of legitimate interrupts), so adding the sync should be a
net gain over doing nothing.
If the consensus is that a read should be done anyway, I can resumbit
the patch that way; I just think it's overkill given that a 100%
guarantee isn't required for correctness.
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