[PATCH] qe_ic: Do a sync when masking interrupts.
galak at kernel.crashing.org
Tue Oct 24 03:52:26 EST 2006
On Oct 23, 2006, at 10:19 AM, Scott Wood wrote:
> Paul Mackerras wrote:
>> 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.
> Possibly -- but the only problem on the rare occasions where the
> 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
> (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?
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