On Wed, 2008-08-06 at 08:25 -0600, Matthew Wilcox wrote: > On Wed, Aug 06, 2008 at 03:06:21PM +0100, Hugh Dickins wrote: > > Commit e0597d70012c82e16ee152270a55d89d8bf66693 (sd: Identify DIF protection > > type and application tag ownership) says that if a disk is formatted with > > Inquiry bit PROTECT=1, it is required to support Read Capacity(16). But my > > SD cards, accessed by builtin cardreader and generic USB storage, disagree. > > > > Therefore fall back to the familiar Read Capacity if Read Capacity(16) fails: > > without even showing the "failed" message since I expect this will be common. > > How about we flip it around? Unconditionally try READ CAPACITY 16 first, > then if that fails, try READ CAPACITY? I suppose there's always the > possibility that a drive will go tits-up if it receives the RC16 > command, so maybe we'll need a blacklist. I don't think so ... the read capacity logic looks the way it does because we had a bit of trouble with USB devices simply going out to lunch on READ_CAPACITY(16) ... otherwise we'd have done the 16 then fallback to 10 ages ago. The best way is probably a blacklist for protect ... I assume there's no plans in the near future for USB to support it, so we could just turn it off globally in USB slave configure. James -- 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
