On Wed, Aug 21, 2013 at 10:23 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > Okay. You can add > > Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > > and submit it as a version-2 patch. I think Greg will add the ack, so needn't v2. > > By the way, even though it's a little late to ask this... Why did you > decide to move only the giveback routine into a tasklet, instead of > moving the entire interrupt handler? Looks below reasons in my mind before preparing the tasklet patch: 1, from my observation, on ARM, the most time-consuming part is dma mapping, unmapping and data copy over coherent memory, so moving giveback out of interrupt handler can decrease USB irq handling time a lot. 2, moving giveback out of irq handler can be done in usbcore, so changes can be minimized. 3, driver's complete() may do many driver specific things which may increase irq handling time randomly, so moving complete() to tasklet can help to decrease HCD irq handling time. Also moving only the giveback routine into a tasklet can avoid dropping HCD private lock during irq handler, which may simplify HCD code, and I have figured out ehci cleanup patches for this. Thanks, -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
