On Tue, Feb 05, 2013 at 04:47:05PM +0000, Mark Brown wrote: > On Tue, Feb 05, 2013 at 05:21:48PM +0100, Linus Walleij wrote: > > > For IRQ mode, use the completion callback to push each cookie > > to NAPI, and thus let the IRQ drive the traffic. > > The whole purpose of NAPI is to avoid taking interrupts for completion > of transfers. Anything that generates interrupts when NAPI is in > polling mode is defeating the point.
Yes, but you're missing one very important point. If your DMA engine is decoupled from the network device, and the DMA engine relies upon interrupts to queue further transfers to move data into RAM, then you have two options: 1. Receive these interrupts so you can update the DMA engine for further data transfer. 2. Don't receive these interrupts, and cause the network device to error out with a FIFO overrun because its DMA requests have not been serviced. (which may raise an interrupt.) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
