By default, the driver IRQ routine should return IRQ_HANDLED as it is a bug to return IRQ_NONE when the driver has actually handled that interrupt.

缺省情况下，驱动程序IR Q例程应该返回IRQ_HANDLED，当驱动程序正在处理那个中断时却返回了IRQ_NONE，说明存在bug。

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Nadal missed the Olympics and the U.S. Open and the early winter season, and ruled himself out of an expected return at the Australian Open with a stomach bug.

WSJ: Jason Gay: Nadal, Tennis's Snuffleupagus

Levels of the winter vomiting bug dipped over the Christmas period, but are likely to go up again as people return to work and school, experts say.

BBC: Winter vomiting bug norovirus levels dip over Christmas