* Andrew Morton <[email protected]> wrote:
> Without having looked at it very hard, I'd venture that this is a
> false positive - that driver uses disable_irq() to prevent reentry
> onto that lock.
correct.
> It does that because it knows it's about to spend a long time talking
> with the mii registers and it doesn't want to do that with interrupts
> disabled.
i still consider it a 'quirky' locking construct, because disabling
interrupts for a long time also disables all other devices sharing the
same IRQ line - not nice.
Also, this is a really hard case for lockdep to detect automatically.
(fortunately it's also relatively rare)
OTOH, the straightforward lockdep workaround would be to take the
spinlock and thus disable all local interrupts - not too nice either.
Albeit in some ways it's still a bit nicer conceptually than disabling
the irq line, because other CPUs are still operational, and under
certain locking designs [preempt-rt] spin_lock_irq() does not disable
local interrupts.
Steve, can you think of any better solution? I dont have this card.
Ingo
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