Re: Disk wakeup on resume

[Phillip Susi <psusi@ubuntu.com>]

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On 11/5/2013 10:56 AM, Douglas Gilbert wrote:
> I think that you might find that almost any SCSI command
> (translated to its ATA equivalent command) will wake up a SATA
> disk. Perhaps just this sequence: fd = open(<ata_bloc_device>) ;
> close(fd) ; is sufficient.

No, otherwise hdparm, udisks, etc would not be able to issue the CHECK
POWER command without waking the disk.  Most commands do wake the
drive, but as far as I can see, nobody is sending down any, and more
importantly, the wake is happening within the kernel pm resume path,
not by userspace after resume.


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