https://bugzilla.kernel.org/show_bug.cgi?id=80711 --- Comment #11 from d gilbert <dgilbert@xxxxxxxxxxxx> --- On 14-08-20 03:15 PM, Alan Stern wrote: > On Tue, 19 Aug 2014, Christoph Hellwig wrote: > >> On Thu, Aug 07, 2014 at 11:58:37AM -0400, Alan Stern wrote: >>>> On Wed, Aug 06, 2014 at 04:02:22PM -0400, Alan Stern wrote: >>>>>> I doubt either of them forces users to hack up flags for these cases. >>>>> >>>>> Why was this change needed in the first place? There's no explanation >>>>> in the patch itself. >>>> >>>> Which chance? The one to not support SG_FLAG_LUN_INHIBIT? >>> >>> No, the patch that started this Bugzilla entry. Tiziano says it is >>> needed in order to send vendor-specific commands that use the LUN bits >>> in CDB[1]. >> >> Yes, I'd really like to know the exact scenario. What kind of command >> is this and who sends it? > > I don't know what the command is, but Tiziano is sending it via the > SCSI-generic (sg) interface. > > In the meantime, I have made a little progress with Windows. It turns > out there are two reasons my earlier test didn't work: > > I didn't bother to set up a valid serial number for the test > device, and Windows wants to see the serial number. > > Windows wants at least one of the logical units to be > removable. > > After those issues were fixed, the host did recognize both logical > units. I tested with two devices, one reporting an ANSI SCSI level of > 0 and the other 2. In both cases, Windows 7 does _not_ stick the LUN > value into the high bits of CDB[1]. > > This suggests that we shouldn't be doing that either, for USB > mass-storage devices. But I'm reluctant to change it because of the > possibility of regressions, not to mention the fact that it would > violate the SCSI spec. > > Suggestions? Perhaps we could add another bit flag in struct scsi_host_template such as: unsigned int transport_says_dont_scsi2_lun_cmd:1; then drivers/usb/storage/scsiglue.c could set that bit in its usb_stor_host_template and drivers/scsi/scsi.c could take heed (and not mask cmd->cmnd[1] with the LUN). Doug Gilbert -- You are receiving this mail because: You are the assignee for the bug.-- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
