Re: [PATCH] PHYLIB: IRQ event workqueue handling fixes

["Maciej W. Rozycki" <macro@linux-mips.org>]

On Fri, 19 Oct 2007, Jarek Poplawski wrote:

> But then... your patch seems to make it possible, because it enables
> irq to the initial state of the counter. Of course, this could happen
> on closing only.

 That's because free_irq() does not disable the interrupt in the correct 
manner.  The scenario is more or less like this:

phy_interrupt()				[depth == 0]
	disable_irq()
		depth++; status |= IRQ_DISABLED;
...
free_irq()				[depth == 1]
	status |= IRQ_DISABLED;
...
phy_change()				[depth == 1]
	enable_irq()
		depth--; status &= ~IRQ_DISABLED;
		oops!

Now if free_irq() correctly incremented the depth counter, then the last
enable_irq() would still decrement it, but with its initial value of 2 it 
would not change the status to reenable the line.

  Maciej
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/