On 08/08/2012 07:46 AM, Kumar Gala wrote:
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On Jul 24, 2012, at 5:20 AM, Jia Hongtao wrote:
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Power supply for PCI inbound/outbound window registers is off when
system
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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
+++++++++++++++++++++++++++++++++
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2 files changed, 122 insertions(+), 1 deletions(-)
Remind me why we need to save/restore PCI ATMUs, why not just
re-parse the device tree to restore?
- k
Save/restore is the more efficient way. Latency of sleep/wakeup is
one of most important features in power management.
-Hongtao.
I don't think the time it takes to run through setup_pci_atmu() is
that long compared to fsl_pci_resume().
Also, don't you need to setup PCICCSRBAR and do setup_pci_cmd() on
resume?
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- k
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.
How do you know you're not just getting lucky? Maybe it only survives
deep sleep up to a certain duration, or under other specific circumstances.
Can you find anywhere that documents what state will be retained during
deep sleep, or ask an appropriate hardware designer?
-Scott