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

- From: Kumar Gala \<hidden\>
- Date: 2012-08-07 17:34:24 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2012/08/9470715
- Thread: https://ratatoskr.run/linuxppc-dev/2012/07/9470407/t.md

```text

On Aug 7, 2012, at 10:34 AM, Scott Wood wrote:

> On 08/07/2012 05:11 AM, Jia Hongtao-B38951 wrote:
>>=20
>>=20
>>> -----Original Message-----
>>> From: Kumar Gala [mailto:<redacted>]
>>> Sent: Tuesday, July 31, 2012 9:37 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 30, 2012, at 1:09 AM, Jia Hongtao-B38951 wrote:
>>>=20
>>>>> -----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.
>>>>>>=20
>>>>>> 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
>>>>=20
>>>> Save/restore is the more efficient way. Latency of sleep/wakeup is =
one
>>>> of most important features in power management.
>>>>=20
>>>> -Hongtao.
>>>=20
>>> I don't think the time it takes to run through setup_pci_atmu() is =
that
>>> long compared to fsl_pci_resume().
>>>=20
>>> Also, don't you need to setup PCICCSRBAR and do setup_pci_cmd() on =
resume?
>>>=20
>>> - k
>>=20
>> Hi Kumar,
>> I did some tests on P1022DS and found out that PCI_CMD and PCICSRBAR =
is not
>> lost when system in deep sleep. We don't need to save it.
>=20
> How does the PCI code know you're entering deep sleep and not =
hibernation?
>=20
> -Scott
>=20

Also, are you sure PCICSRBAR does not need restoring?  I'd be surprised =
if PCICSRBAR was ok, but the ATMUs where not.

- k
```