Re: WD_QUIRK_FORCE_LBA48

[Michael van Elst <mlelstv%serpens.de@localhost>]

On Tue, Dec 15, 2009 at 10:30:49AM +0100, Manuel Bouyer wrote:

> > ATA6 (at least the draft I have) shows the same rules and ATA5
> > doesn't have LBA48.
> 
> Yes that's more or less what I meant. ATA6 says that words 60-61
> should be less than or equal to 0x10000000,
> which means we can address
> sectors 0-0xfffffff using LBA28.


ATA5

6.2.1 Definitions and value ranges of IDENTIFY DEVICE words (see 8.12)

11) Words (61:60) shall contain the total number of user-addressable
    sectors. The content of words (61:60) shall be greater than or
    equal to one and less than or equal to 268,435,456.


ATA6

6.2.1 Definitions and value ranges of IDENTIFY DEVICE words (see 8.12)

1) Words (61:60) shall contain the value one greater than the total
   number of user-addressable sectors in 28-bit addressing and shall
   not exceed 0FFFFFFFh. The content of words (61:60) shall be greater
   than or equal to one and less than or equal to 268,435,455.

Both versions say that LBA28 commands shall fail if the requested
LBA is larger or equal to the number in (61:60). So the wording
in ATA6 regarding "one greater than the total number" is bogus
and probably not implemented correctly by some devices.


-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."