On Thu, 2017-05-18 at 10:35 -0400, Alan Stern wrote: > This is in reference to > > https://bugzilla.redhat.com/show_bug.cgi?id=1351305 > > The problem is that some program (probably udisks2) periodically sends > the following ATA pass-through command to a USB-ATA bridge attached to > a Western Digital drive: > > 85062000 00000000 00000000 0000e500 According to T10 SAT-4 this is an ATA PASS-THROUGH(16) command, with PROTOCOL=3 (non-data), CK_COND=1, COMMAND=E5h (the ATA command). > > I don't know what this command does (some sort of reset?). The command > fails and the device returns the following sense data: > > 72000000 0000000e 090c0000 00ff0000 00000000 0050 > > I don't know how to decode this -- I don't have copies of the relevant > documents. Can anybody decode this for me? This is a current descriptor format sense data wih a single ATA Status Return sense data descriptor (beginning at 8 bytes into the sense data buffer 090c...) The relevant fields are COUNT=255 LBA=0 and STATUS=50h (which I suspect is what is the interesting part). > > Anyway, the SCSI core treats it as a Hardware Error and puts warning > messages in the kernel log: > > [17244.280612] sd 7:0:0:0: [sdd] tag#0 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_SENSE > [17244.280614] sd 7:0:0:0: [sdd] tag#0 Sense Key : Hardware Error [current] [descriptor] > [17244.280616] sd 7:0:0:0: [sdd] tag#0 Add. Sense: No additional sense information > [17244.280618] sd 7:0:0:0: [sdd] tag#0 CDB: ATA command pass through(16) 85 06 20 00 00 00 00 00 00 00 00 00 00 00 e5 00 > > Is this really the right thing to do? Could it be that we are failing > to interpret this sense data correctly? With the 72000000 0000000e 090c0000 00ff0000 00000000 0050 sense data buffer above scsi_sense_key_string() should have returned "No Sense" as the array value is 0. Even if we somehow managed to fail to correctly interpret descriptor format sense vs. fixed format sense. > > Other commands provoke similar responses from the device, but without > obnoxious log messages. For example, the command: > > 85082e00 00000100 00000000 0000ec00 > > fails with the following sense data: > > 72000000 0000000e 090c0000 00000000 00000000 0050 > > and no output to the log. I don't know why the behavior is different. > There are other similar examples, with and without log messages. It seems more likely that somehow there is a path where the wrong or uninitialized sshdr structure is being passed to the logging routine. -Ewan > > Any help would be appreciated. > > Alan Stern >
