Re: [PATCH RFC] ahci: implement handoff quirk

[Robert Hancock <hancockrwd@gmail.com>]

On 12/17/2009 12:34 AM, Jeff Garzik wrote:
> On 06/17/2008 11:37 PM, Tejun Heo wrote:
>> ahci 1.2 has an exciting! new feature called BIOS/OS handoff which
>> basically is there to allow BIOS to keep tinkering with the controller
>> even after OS starts executing. I have no idea what this is useful
>> for but it's there and we need to do it.
>>
>> This patch implements the handoff as FIXUP_HEADER as the controller
>> needs to be claimed before the OS changes any configuration including
>> IRQ routing.
>>
>> I'm yet to see any controller which actually requires this, so it's
>> not for inclusion yet. Maybe keep this in a separate branch?
>>
>> RFC, DON'T COMMIT
>> ---
>> drivers/pci/quirks.c | 109
>> +++++++++++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 109 insertions(+)
>
> Looking through old emails... did AMD ever confirm the usefulness of
> this patch? Is it actually needed in the field? I'm guessing the silence
> implies "No"... :)

Well, we only implemented the feature bit displaying for the BOH 
"capability" recently, so I guess we wouldn't likely have seen it if 
something did advertise it. However, it's true I don't know why any sane 
BIOS would want to do this. Can't hurt to have the support, however..