On Fri, Nov 25, 2016 at 01:50:35PM +0000, Måns Rullgård wrote: > Russell King - ARM Linux <linux@xxxxxxxxxxxxxxx> writes: > > It would be unfair to augment the API and add the burden on everyone > > for the new API when 99.999% of the world doesn't require it. > > I don't think making this particular dma driver wait for the descriptor > callback to return before reusing a channel quite amounts to a horrid > hack. It certainly wouldn't burden anyone other than the poor drivers > for devices connected to it, all of which are specific to Sigma AFAIK. Except when you stop to think that delaying in a tasklet is exactly the same as randomly delaying in an interrupt handler - the tasklet runs on the return path back to the parent context of an interrupt handler. Even if you sleep in the tasklet, you're sleeping on behalf of the currently executing thread - if it's a RT thread, you effectively destroy the RT-ness of the thread. Let's hope no one cares about RT performance on that hardware... -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
