Alan Stern wrote: > On Wed, 23 Jun 2010, Stanislav Brabec wrote: > And here is where the problem occurs: > > > ffff880110466180 2399912185 S Bo:7:004:2 -115 31 = 55534243 11000000 00000000 00000600 00000000 00000000 00000000 000000 > > ffff880110466180 2399913155 C Bo:7:004:2 0 31 > > > ffff880110466180 2399913170 S Bi:7:004:2 -115 13 < > > ffff880110466180 2400250157 C Bi:7:004:2 0 13 = 55534253 11000000 00000000 01 > > The command above is TEST UNIT READY. The device replied with Check > Condition status, indicating that it was not ready. Therefore > usb-storage had to send a REQUEST SENSE command in order to learn what > was wrong: > > > ffff880110466180 2400250169 S Bo:7:004:2 -115 31 = 55534243 12000000 12000000 80000603 00000012 00000000 00000000 000000 > > ffff880110466180 2400252160 C Bo:7:004:2 0 31 > > > ffff8800c05bc9c0 2400252177 S Bi:7:004:2 -115 18 < > > ffff8800c05bc9c0 2400588162 C Bi:7:004:2 -121 0 > > ffff880110466180 2400588176 S Bi:7:004:2 -115 13 < > > ffff880110466180 2400589164 C Bi:7:004:2 0 13 = 55534253 12000000 12000000 01 > > That was the REQUEST SENSE command. It also failed; the device did not > return any sense information. This is the "incomplete SCSI frame" you > suspected. (The "short read transfer" message above occurred at this > point; the device sent 0 bytes of sense data instead of 18 bytes as it > should have.) Failure to send the sense data is clearly a bug in the > scanner. But the same scanner worked perfectly with dc395 PCI SCSI card. > usb-storage treats failure of REQUEST SENSE as an error requiring a > device reset. The remainder of the usbmon log shows the reset, which > worked. But resets are always followed by TEST UNIT READY, to verify > the device's status after being reset, and the same sequence of events > repeated -- over and over again. That's why your scan didn't work. Thanks for the analysis. Is there a chance for a work-around that could be accepted to the vanilla? ________________________________________________________________________ Stanislav Brabec http://www.penguin.cz/~utx -- 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
