How long is it okay to busy-wait with interrupts disabled? Are there any clear-cut guidelines? My feeling is that for ordinary desktop use, 1-2 ms should be about the limit, but other people may feel differently. (There's one spot in ehci-hcd where the delay can last up to 250 ms, which does seem rather excessive. Fortunately it never takes that long unless the hardware is broken.) No doubt the RT people would say the upper bound should be on the order of a few microseconds or less. I'd be happy to change ehci-hcd, which has several delays in the 1-2 ms range -- but they tend to be nested inside routines that are called within the scope of spinlock_irq, which means a fair amount of rewriting would be needed. Any thoughts or recommendations? Alan Stern -- 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
