On Wed, May 06, 2009 at 03:51:14PM -0500, Jason Wessel wrote: > Greg KH wrote: > >> Doing enough printk's such as in register_console() will cause loss > >> because you run out of URBs unless you can force them to complete. > >> > > > > Why not just make the upper bound of urbs very large? We used to have > > an unlimited number of in-flight urbs for some drivers until it was > > pointed out that a simple: > > cat /dev/null > /dev/ttyUSB0 > > would cause a DoS :) > > > > What happens if your upper bound is 400? 4000? Will that work > > properly? > > > Sure, if you have enough of a urb available, ultimately you get all the > printk's. Good, then you just solved your issue with no nasty host driver hack. > If I want to printk from the nmi_watchdog out to this device, am I going > to get anything if the write is not synchronous, because in theory the > hcd device is never going to get accessed again? No you are not, sorry, USB doesn't work without interrupts in this kind of mode at all. > Ideally I want to make sure that somehow I get my debug output out to > the console, even if it means we do some polling after the oops state is > set. That's going to be "interesting" to try to accomplish :) good luck, greg k-h -- 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
