-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 1/9/2014 1:29 PM, Douglas Gilbert wrote: > When REQUEST SENSE had its original semantics, TEST UNIT READY was > the only game in town for monitoring power management. From my > reading of spc4r36n.pdf section 5.1.2 "Important commands for all > SCSI device servers" TEST UNIT READY should be called before > REQUEST SENSE during device initialization (including resume). If > the responses to TEST UNIT READY and REQUEST SENSE contradict then > the former is correct. I don't see language there remotely like that. How did you arrive at this conclusion? > There are SCSI devices out caught in that transition. For example > with sg_format I monitor progress with either TEST UNIT READY or > REQUEST SENSE, defaulting to the former. [Progress indication is > another new role for REQUEST SENSE.] > > Note that the billion or so USB keys out there that say that they > comply with SCSI-2 should respond to a REQUEST SENSE with its > original semantics. Then they will return 0/0/0, so we will assume they are up and running, which is correct. SPC-2 is coming up on 13 years old and listed this usage for REQUEST SENSE. Are there any actual disk drives out there ( and still in use ) that return 0/0/0 when in the stopped state? I can't imagine there would be. > The ATA REQUEST SENSE DATA EXT command refers to the SPC-4 > "standard" (not yet it ain't) which is naturally the new SCSI > semantics of REQUEST SENSE. I believe the ATA REQUEST SENSE DATA > EXT command is a relatively new ATA command so it does not carry > the historical baggage of its SCSI counterpart. It is also only for ATAPI devices. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (MingW32) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJSzvaMAAoJEI5FoCIzSKrwcxIH/3Y7DdnXr6Fj9MiWs/Hn2kte EZVkHbj5jN4/OdKj3gnR3BK8gjrA7AEtbD3J6g7zJSj50UM1EA5RqMYAutZQkvYk UsKNuV+qIcN3OpSltAGK5TQPGUo2M9apcYuy9NKTZEaWI9dXejGJ/2GitxYXO35H drsTNlzEErnQvJwBhEYq6+rtferv7/vdZOljSGM1pP48gK0IWz+r2cwXxojkUvk1 lsiU97BxHCVNJc7kHmKVzBw0JV4R2mrtI/I/bE/VZzeljvjA9fNoXqdQxFU1RPDT PNLHBecjgbDlc70l1CNKNc4ApqBDSYg9SwBtG1nCa36MLgLoN1ZDEatzqT9IdYw= =qsZP -----END PGP SIGNATURE----- -- 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
