Re: [patch 2a/3] Expose Power Management Policy option to users

From: Jeff Garzik
Date: Thu Jun 14 2007 - 13:44:39 EST

Kristen Carlson Accardi wrote:
Ok - sorry for my ignorance about SCSI - but my sources (i.e. Arjan) tell me that the problem is that Link in ATA land means something different than Link in SCSI land, and that what I really need to do is leave this code under
the Host class, but rename it to something that more accurately reflects
what it means under SCSI.

James' analogy holds, and is even more true once SATA Port Multipliers are in the picture. Then you have remote SATA phys. And James has essentially stated a long term libata problem: libata wants its own ATA transport class, and perhaps a cleaning-up and coalescing of the in-kernel SATA phy objects and processes.

The main difference is that SATA doesn't have to worry about target phys and initiator phys, largely just the initiator phy. And phys in SATA don't have unique identifiers (WWNs).

I don't think we should delay ALPM in order to complete phy objects and an ATA transport class. But OTOH a transport class may be the best place to put these new sysfs nodes. But#2, that train of logic leads one down the road of implementing a minimal ATA transport class across all supported ATA devices, which is something that probably only James is an expert at (transport classes that is, not ATA).

Should I rename the file to "segment_power_management_policy"?



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