On Fri, 15 Jun 2007, Oliver Neukum wrote: > > > 2. Can the SCSI layer deal with partially executed sg requests? > > > > Yes for READs and WRITEs; I'm not sure about other sorts of requests. > > > > But you're much better off avoiding partially executed requests if you > > can avoid it. It would be preferable to transmit the data one packet > > at a time: slower but more likely to succeed. > > Why is that better? The problem is unlikely to be unique to USB > and should therefore be handled in common code if possible.
Partially-executed requests normally arise because the device reports a failure in the middle of a transfer. The SCSI core is designed to handle such things. But you're talking about breaking an already-setup command into multiple commands. For each piece to work you would have to modify the contents of the SCSI command block sent to the device and fool the SCSI core in other ways. It isn't recommended. If a command really does need to be broken up, it should be done at the SCSI level instead of the driver level. 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
