Re: [PATCH PROPOSAL] libata/pci: Move D3 hack handling from libata into PCI

[Alan Cox <alan@lxorguk.ukuu.org.uk>]

On Thu, 24 Jul 2008 13:11:24 -0700
Jesse Barnes <jbarnes@virtuousgeek.org> wrote:

> On Thursday, July 24, 2008 9:18 am Alan Cox wrote:
> > Libata has some hacks to deal with certain controllers going silly in D3
> > state. The right way to handle this is to keep a PCI device flag for such
> > devices. That can then be generalised for no ATA devices with power
> > problems.
> >
> > Signed-off-by: Alan Cox <alan@redhat.com>
> 
> Looks pretty reasonable to me; do you want me to take the drivers/ata bits 
> along with the PCI stuff?
> 
> Btw, what happens to these devices in D3hot?  Do they behave like they're in 
> D3cold or something and require a reset?  Or do they otherwise kill the bus 
> somehow?

They lose some of their configuration bits in a manner we can't restore.
The end effect of that is that if we disable/re-enable them they can't be
put back into proper DMA mode.

Windows it seems doesn't do this to these devices and the BIOS re-inits
the legacy ATA controllers during boot up which makes suspend/resume work.

Alan