On Wed, 9 May 2012, Norman Diamond wrote: > >>> There definitely are some bridges which handle ATA passthru correctly. > >> > >> Oh, please can you suggest some.� I search occasionally but have > >> never found one that was described as obeying ATA passthru.� Of > >> course I can't command my users to use such bridges, but I would like > >> to use one or two. > > > > The only ones I'm aware of are the entries marked with the SANE_SENSE > > quirk in unusual_devs.h: the HP Personal Media Drive (03f0:070c), the > > Genesys Logic bridge (05e3:0723), the Seagate FreeAgent Pro > > (0bc2:3010), the Maxtor bridge (0d49:7310), the Western Digital bridge > > (1058:0704), and a different JMicron bridge (152d:2329).� Of course, > > the fact that the flag is set doesn't necessarily mean the device > > really does have SAT support. > > Among those, the Genesys and JMicron ones look like they have a > chance of being used in adapters sold separately from Seagate and > Western Digital external drives. By any chance do you know of cables > or docking stations that use them? Unfortunately I don't. Maybe somebody on the mailing list can suggest something. > >>> ��� CAPACITY_10_AND_16: Issue both READ CAPACITY and READ > >>> ��� CAPACITY(16), and if READ CAPACITY(16) gives a result > 2 TB > >>> ��� and READ CAPACITY doesn't give 0xffffffff, truncate the size to > >>> ��� 2 TB; > >>> > >>> ��� CAPACITY_HEURISTICS_63: Don't decrement the capacity if > >>> ��� the reported capacity is a multiple of 63, but otherwise behave > >>> ��� like CAPACITY_HEURISTICS; > >>> > >>> ��� TEST_CAPACITY: Try to do a single-block read of the last > >>> ��� reported block. > > > > What I'm wondering is whether it's appropriate to have three separate > > flags for these things, or whether some subset of them should be > > controlled by the same flag -- maybe a flag that would be set only for > > devices that are known to be bridges. > > They are three separate operations, and you've pointed out there's a > chance that some devices might crash on some of them and not others, > so it would be a good idea to make three separate flags. True enough. And while there's no justification for applying CAPACITY_HEURISTICS_63 to anything but a bridge, the other two have a distinct possibility of crashing some devices. Therefore none of them should be applied blindly. Alan Stern -- 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
