On 01/08/2014 09:53 AM, Phillip Susi wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA512 > > On 01/07/2014 08:32 PM, Aaron Lu wrote: >> The ATA and SCSI devices are all resumed in my patches, notice >> there is a single pm_request_resume call in both ATA and SCSI's >> system resume callback, so the runtime status and the disk's state >> is synced. The pm_request_resume call is asynchronous to the system >> resume, so it doesn't block system resume. >> >> But I see your point, my patch will not achieve that, it can only >> speed up S3 for a typical PC with a traditional disk. I can omit >> the pm_request_resume call in the system resume callback, but then >> if the disk is spun up by itself, then the runtime status indeed >> doesn't reflect the actual state. I suppose for SATA controllers >> that support Staggered Spin-up wouldn't do this? > > Ahh, yes, the point of my patches was to avoid waking a disk at all if > possible, and avoid blocking on it otherwise. Todd Brandt's patches > just backgrounded the resume. > > As far as I can tell, the AHCI staggered spinup feature is only a hint > to the libata driver that it should not probe all disks in parallel. I thought that feature is used to control if a disk should be spun up once powered from the host side. > The way to get an ATA disk to not spin itself up is by enabling the > Power on in Standby feature, either through hdparm, or via a jumper, Too bad for a jumper, that's beyond our control. And about the hdparm, does the setting survive a power cycle? -- 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
