# RE: \[PATCH 5/6\] powerpc/fsl-pci: Add pci inbound/outbound PM support

- From: Jia Hongtao-B38951 \<hidden\>
- Date: 2012-07-30 06:09:57 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2012/07/9470552
- Thread: https://ratatoskr.run/linuxppc-dev/2012/07/9470407/t.md

```text
> -----Original Message-----
> From: Kumar Gala [mailto:<redacted>]
> Sent: Friday, July 27, 2012 9:24 PM
> To: Jia Hongtao-B38951
> Cc: <redacted>; Wood Scott-B07421; Li Yang-R58472
> Subject: Re: [PATCH 5/6] powerpc/fsl-pci: Add pci inbound/outbound PM
> support
>=20
>=20
> On Jul 24, 2012, at 5:20 AM, Jia Hongtao wrote:
>=20
> > Power supply for PCI inbound/outbound window registers is off when
> system
> > go to deep-sleep state. We save the values of registers before suspend
> > and restore to registers after resume.
> >
> > Signed-off-by: Jiang Yutang <redacted>
> > Signed-off-by: Jia Hongtao <redacted>
> > Signed-off-by: Li Yang <redacted>
> > ---
> > arch/powerpc/include/asm/pci-bridge.h |    2 +-
> > arch/powerpc/sysdev/fsl_pci.c         |  121
> +++++++++++++++++++++++++++++++++
> > 2 files changed, 122 insertions(+), 1 deletions(-)
>=20
> Remind me why we need to save/restore PCI ATMUs, why not just re-parse
> the device tree to restore?
>=20
> - k

Save/restore is the more efficient way. Latency of sleep/wakeup is one of
most important features in power management.

-Hongtao.
```