On Wed, 11 Jul 2007, jidong xiao wrote: > Ok,let's talk about the timeout handling routine,we defined a > timeout_handler in drivers/usb/storage/transport.c,inside that > function,we will call usb_unlink_urb,why cannot we sleep?what impact > if the driver go to sleep here?
In addition to what Oliver said, you should realize that there are situations where the kernel must not sleep. For example, the kernel is not allowed to sleep in an interrupt handler or any sort of bottom-half handler. Since timer routines are a form of bottom-half, they cannot sleep. If the driver did try to call usb_kill_urb, you would get a big fat error message on the screen and your system might crash. Alan Stern ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
