On 10/24/2010 10:37 AM, Alan Cox wrote: >> The generic code does not invoke the write_room callback before invoking >> break_ctl, so there is no way to use this function in usb_serial. >> > Why would it ? > > Oops, typo... Last sentence was supposed to end with "in usb_debug". usb_debug invokes usb_serial_generic_write from break_ctl and ignores the result; therefore, if there is no room in the generic write FIFO, the write will fail. However--usb_debug _only_ uses usb_serial_generic_write for break_ctl; so if there is no room, it is because of a previous (uncompleted) break_ctl, and according to standard UART semantics there is no difference between one break and two... -a -- 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