On Aug 9, 2012, at 12:05 AM, Li Yang wrote: > On Thu, Aug 9, 2012 at 10:52 AM, Jia Hongtao-B38951 > <b38...@freescale.com> wrote: >> >> >>> -----Original Message----- >>> From: Linuxppc-dev [mailto:linuxppc-dev- >>> bounces+b38951=freescale....@lists.ozlabs.org] On Behalf Of Kumar Gala >>> Sent: Wednesday, August 08, 2012 8:47 PM >>> To: Jia Hongtao-B38951 >>> Cc: Wood Scott-B07421; linuxppc-dev@lists.ozlabs.org; Li Yang-R58472 >>> Subject: Re: [PATCH 5/6] powerpc/fsl-pci: Add pci inbound/outbound PM >>> support >>> >>>>>>>>> >>>>>>>>> On Jul 24, 2012, at 5:20 AM, Jia Hongtao wrote: >>>>>>>>> >>>>>>>>>> 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 <b14...@freescale.com> >>>>>>>>>> Signed-off-by: Jia Hongtao <b38...@freescale.com> >>>>>>>>>> Signed-off-by: Li Yang <le...@freescale.com> >>>>>>>>>> --- >>>>>>>>>> arch/powerpc/include/asm/pci-bridge.h | 2 +- >>>>>>>>>> arch/powerpc/sysdev/fsl_pci.c | 121 >>>>>>>>> +++++++++++++++++++++++++++++++++ >>>>>>>>>> 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? >>>>>>> >>>>>>> - 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 does the PCI code know you're entering deep sleep and not >>> hibernation? >>>>> >>>>> -Scott >>>> >>>> When system come back from hibernation PCI will be initialized again. >>>> So no need to save PCI_CMD and PEXCSRBAR. >>>> >>>> -Hongtao. >>>> >>> >>> What do you mean PCI will be initialized again? What code path are you >>> talking about that would set PCI_CMD & PEXCSRBAR? >>> >>> - k >> >> >> In hibernation mode: >> >> When system come back from hibernation kernel will start up again. >> Before loading hibernation image PCI initialization has already done. >> Some other hardware also re-init again. > > In current Linux implementation, restoring from hibernation image is > using late initcall. By that time, all the platform devices are > already initialized like a fresh boot. > > - Leo
I ask against, what specific code path (I'd like a call trace) would cause PCI_CMD and PEXCSRBAR to be set in the wakeup case? - k _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
