Alan Cox wrote:
On Fri, 21 Nov 2008 13:13:06 +0900
Tejun Heo <tj@xxxxxxxxxx> wrote:
The DMA_IRQ bit in the bmdma status register is always set when IDEIRQ
is asserted allowing spurious IRQ detection. Detect spurious IRQs and
clear them. This protects ata_piix against nobody-cared which gets
reported not so rarely.
Various controllers have the ability to report the IRQ more reliably in
similar fashion, should this not be part of ata_sff_interrupt with an
optional ops->irq_pending call ?
Though I'm in general agreement with this sub-thread of opinions, I do
note that, in the past, I have purposefully avoided an ->irq_pending.
I always felt the alternative -- writing a small irq handler function
specifically for that controller -- was a much more flexible and
powerful method of producing the desired result.
A separate interrupt function can, for example, perform an MMIO read to
check irq-pending, outside of a spinlock. ->irq_pending callback is a
bit more constraining.
In terms of implementation, we could probably collapse all the
non-controller-specific behavior into a single function call or macro,
performed inside the custom interrupt handling routine.
Jeff
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