On 04/18/2011 08:43 PM, Russell King - ARM Linux wrote: > On Mon, Apr 18, 2011 at 04:52:00PM +0530, Viresh Kumar wrote: >> Few dma controller doesn't support dmaengine_pause() and return -ENXIO if >> dmaengine_pause() is called for them. Error messages such as "unable to pause >> DMA transfer" shouldn't be printed for them. > > It is _required_ to pause the DMA engine at this point, as we need to > read characters via PIO. Leaving the DMA engine active at this point > invites it to transfer additional characters beneath us, before we've > had time to properly update the DMA engine for the characters received. > > So, dmaengine_pause() is a requirement for PL011. > . > Ok. -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
