libata: Media rotation rate and form factor heuristics

This patch provides new heuristics for parsing both the form factor and
media rotation rate ATA IDENFITY words.

The reported ATA version must be 7 or greater and the device must return
values defined as valid in the standard.  Only then are the
characteristics reported to SCSI via the VPD B1 page.

This seems like a reasonable compromise to me considering that we have
been shipping several kernel releases that key off the rotation rate bit
without any version checking whatsoever.  With no complaints so far.

Signed-off-by: Martin K. Petersen <[email protected]>
Signed-off-by: Jeff Garzik <[email protected]>
This commit is contained in:
Martin K. Petersen 2009-05-15 00:40:35 -04:00 • committed by Jeff Garzik
commit 4bca328643
2 changed files with 34 additions and 5 deletions

View file

@ -2142,13 +2142,14 @@ static unsigned int ata_scsiop_inq_89(struct ata_scsi_args *args, u8 *rbuf)
static unsigned int ata_scsiop_inq_b1(struct ata_scsi_args *args, u8 *rbuf)
{
int form_factor = ata_id_form_factor(args->id);
int media_rotation_rate = ata_id_rotation_rate(args->id);
rbuf[1] = 0xb1;
rbuf[3] = 0x3c;
if (ata_id_major_version(args->id) > 7) {
rbuf[4] = args->id[217] >> 8;
rbuf[5] = args->id[217];
rbuf[7] = args->id[168] & 0xf;
}
rbuf[4] = media_rotation_rate >> 8;
rbuf[5] = media_rotation_rate;
rbuf[7] = form_factor;
return 0;
}