On Wed, May 20, 2009 at 12:00 AM, Jens Axboe <jens.axboe@xxxxxxxxxx> wrote: > libata currently has a pretty dumb ATA_MAX_QUEUE loop for finding > a free tag to use. Instead of fixing that up, convert libata to > using block layer tagging - gets rid of code in libata, and is also > much faster. ... > @@ -1137,7 +1141,17 @@ static int ata_scsi_dev_config(struct scsi_device *sdev, > > depth = min(sdev->host->can_queue, ata_id_queue_depth(dev->id)); > depth = min(ATA_MAX_QUEUE - 1, depth); > - scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth); > + > + /* > + * If this device is behind a port multiplier, we have > + * to share the tag map between all devices on that PMP. > + * Set up the shared tag map here and we get automatic. Automatic what? > + */ > + if (dev->link->ap->pmp_link) > + scsi_init_shared_tag_map(sdev->host, ATA_MAX_QUEUE - 1); > + > + scsi_set_tag_type(sdev, MSG_SIMPLE_TAG); > + scsi_activate_tcq(sdev, depth); I just read Tejun's reply and it sounds right what he's saying. But can SATA controllers handle NCQ and !NCQ devices on the same port? Can the PMP handle it? If both can, I don't understand how a mixed config works today. TBH, this isn't something I'm very worried about since most commercial configs will be homogenous (think HW replacement/support costs). hth, grant -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
