ATA driver races with interrupts
will+freebsd-current at will.iki.fi
Tue Aug 3 00:25:12 PDT 2004
Søren Schmidt wrote:
> If the controller doesn't have a bit saying if the interrupt is for
> us, then its impossible to close the race completely (without the
> above measures in place). However some devices use the DMA interrupt
> bits even in PIO mode (ie HPT does this) but I have no docs on the
> VIA's on that, but its worth a try at least...
The current situation seems to me like ata_generic_intr can't work for
*any* controller sharing interrupts, even with DMA on a controller that
sets ATA_BMSTAT_INTERRUPT correctly, since if an interrupt occurs before
ATA_DMA_ACTIVE is set, ATA_BMSTAT_PORT is never even checked.
IMHO ch->running != NULL is an insufficient condition based on which to
assume that an interrupt is intended for a specific channel...
Something similar to my patch + disabling interrupts to avoid a race
between the interrupt and ATA_EXPECT_INTR being set should at least
improve the situation. What races would that leave open?
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