From: Krzysztof Halasa <khc@pm.waw.pl>
Date: Sun, 29 Jul 2007 00:25:07 +0200

I wonder if it's dev_kfree_skb_irq() which should but fails to wake
the thing up?

Software interrupts might be getting lost, dev_kfree_skb_irq() has to
queue the kfree_skb() to soft IRQ.

Therefore, dev_kfree_skb_irq() will only work properly from hardware
interrupt context, where we will return and thus run the scheduled
software interrupt.

So some things to check out are whether the driver is invoking
dev_kfree_skb_irq() in the right context, whether ARM might have some
software interrupt processing preculiarity, etc.