Le Thu, 22 Aug 2013 21:39:17 +0100, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> a écrit : > This patch divides ehci-hcd's interrupt handler into a top half and a > bottom half, using a tasklet to execute the latter. > > The conversion is very straightforward. The only subtle point is that > we have to ignore interrupts that arrive while the tasklet is running > (i.e., from another device on a shared IRQ line). > Do you have any reason to use a tasklet instead of a thread for handling the bottom half ? We do some embedded product and we saw some scenario where usb stack and drivers can do lot's of processing in irq context. For example video uvc driver do a copy of the current image in the urb completion handler. And that's harm real time. Moving to tasklet will solve only a part of the problem : other irq won't be delayed by the usb irq handler. But realtime threads will still be preempted by tasklets. Matthieu -- 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
