What's the difference between async and sync unlink?
"jidong xiao" <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
I see there are two routines, usb_unlink_urb and usb_kill_urb,the latter one should be used for sync unlinking,this means it can go to sleep,it won't return until the completion handler have finished.And the former one could not go to sleep.But what's difference between sync and async,I mean,why do we need such two kinds of mechanism to cancel a transfer request? I can find there are such comments in the source code, * When the URB_ASYNC_UNLINK transfer flag for the URB is set, this * request is asynchronous. Success is indicated by returning -EINPROGRESS, * at which time the URB will normally have been unlinked but not yet * given back to the device driver. When it is called, the completion * function will see urb->status == -ECONNRESET. my question is, what would happen if urb->status==-ECONNRESET? Thanks Jason Xiao ------------------------------------------------------------------------- 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/ _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel