Re: [ACPI] Re: RFC: ACPI/scsi/libata integration and hotswap

[Jeff Garzik <jgarzik@pobox.com>]

Alan Cox wrote:
> On Iau, 2005-12-08 at 08:52 -0500, Jeff Garzik wrote:
> 
>>On Thu, Dec 08, 2005 at 01:39:45PM +0000, Matthew Garrett wrote:
>>
>>>On Thu, Dec 08, 2005 at 01:33:08PM +0000, Christoph Hellwig wrote:
>>>
>>>
>>>>Don't do it at all.  We don't need to fuck up every layer and driver for
>>>>intels braindamage.
>>>
>>>Doing SATA suspend/resume properly on x86 depends on knowing the ACPI 
>>>object that corresponds to a host or target.
>>
>>Not true.
> 
> 
> 
> Actually he is right. You have to know the ACPI object in order to run
> the _GTM/_STM etc functions. If you don't run those your suspend/resume

These are only for PATA.  We don't care about _GTM/_STM on SATA.

Further, SATA completely resets and re-initializes the device as if from 
a hardware reset (except on ata_piix, which doesn't support COMRESET, 
and PATA).  This makes _GTF uninteresting, as well.


> may not work, may corrupt and so on. The only safe alternative is to
> disable acpi which, while it would have been a good idea before the spec
> ever got out, is a bit late now.

suspend/resume works just fine with Jens' out-of-tree patch.


> If you don't run the resume methods your disk subsystem status after a
> resume is simply undefined and unsafe.

I initialize the hardware to a defined state.

	Jeff