On Thu, Jul 05, 2012 at 05:40:45PM -0400, Alan Stern wrote: > On Tue, 3 Jul 2012, Matthew Wilcox wrote: > > > I think the necessary algorithm is simpler than that: > > > > Send RC10 (unless the device supports PI, in which case it's probably > > enterprisey and well-tested) > > Send RC16 > > If RC10 capacity agrees with RC16 capacity, use extra RC16 data. > > (for values of "agrees with" that include the "-1 to use RC16" indicator) > > > > Sure, it's one extra command, but really, who cares? > > Well, some USB devices might care. Right now we don't send RC16 to > them at all because they get RC10 first and it indicates a capacity > below 2 TB. Mmm. I think I forgot a step: Send RC10 (unless the device supports PI, in which case it's probably enterprisey and well-tested) If the device indicates a level < SPC_2, stop here Send RC16 If RC10 capacity agrees with RC16 capacity, use extra RC16 data. (for values of "agrees with" that include the "-1 to use RC16" indicator) > In the end, usb-storage may be forced to use the NO_READ_CAPACITY_16 > flag with all devices except those we can positively identify as a > USB-(S)ATA bridge. Is that really an improvement over nobbling the IDENTIFY results to force SCSI_2? -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." -- 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
