Re: [PATCH] libata: write cache and read ahead

[Jeff Garzik <jgarzik@pobox.com>]

Luben Tuikov wrote:
> On 08/22/05 01:12, Douglas Gilbert wrote:
> 
>>I was surprised how much code needed changing.
>>With MODE SELECT's issues with libata addressed
>>various other SAT "extras" should be much easier
>>to implement. That should make libata more attractive
>>as a SAT layer for SAS LLDDs (that don't do it already
>>in firmware).
> 
> 
> Doug, how about never needing a SAT layer for SAS LLDDs
> for ATA/ATAPI devices.
> 
> Would you object if I "give" you a "domain device" to which
> you can send FISes (+ the packet if ATAPI) through
> a SAM-4 intefrace: Execute Task + TMFs?
> 
> Jeff?

SAT is the useful piece of libata that makes everything work.  You can't 
rip out it and still expect to do anything useful ;-)

libata relies on SCSI's device class drivers -- sd, sr, st, sg -- to 
manage devices and generate commands to service.  And in turn, we rely 
on SAT (libata-scsi.c) to translate device class commands into ATA commands.

If the SAT layer went away, then nothing would exist to generate 
commands for libata to service.

	Jeff