Re: [PATCH] libata: device suspend/resume

Jeff Garzik
2005-05-24T07:17:03Z

Hannes Reinecke wrote:
> Jeff Garzik wrote:
> [ .. ]
>
>>Longer term, SATA PM through SCSI will have three facets:
>>
>>* Device PM. This is best handled by the device class driver (sd/sr/st).
>>
>>* Bus PM. This is best handled by the transport class driver (need to
>>write for SATA and SAS).
>>
>>* Host PM. This is handled in the obvious manner, using existing PM
>>driver hooks. PCI D0/D3, etc.
>>
>>I can describe how this will look when libata is divorced from SCSI, if
>>you would like, too...
>
>
> Divorced from SCSI? Care to elaborate?

General Linux thesis: translation and emulation are lame. Adds
needless overhead. One should write a "bare metal" driver.

libata should be able to export a native block driver for ATA devices,
making libata-scsi.c simply an optional "T10 SAT implementation" that
users can retain for compatibility and certain features, or excise for
lower overhead.

As ATAPI is converging with SCSI MMC -- the two committes are actively
aligning the standards -- I would prefer to handle ATAPI devices through
the SCSI layer.

Jeff