[PATCH 2/2] fsl/pci: The new pci suspend/resume implementation

[Dongsheng.Wang at freescale.com]

> -----Original Message-----
> From: Rafael J. Wysocki [mailto:rjw at rjwysocki.net]
> Sent: Wednesday, January 08, 2014 4:42 AM
> To: Wang Dongsheng-B40534
> Cc: bhelgaas at google.com; Wood Scott-B07421; galak at codeaurora.org; Zang Roy-
> R61911; linux-pci at vger.kernel.org; linuxppc-dev at lists.ozlabs.org
> Subject: Re: [PATCH 2/2] fsl/pci: The new pci suspend/resume implementation
> 
> On Tuesday, January 07, 2014 04:04:08 PM Dongsheng Wang wrote:
> > From: Wang Dongsheng <dongsheng.wang at freescale.com>
> >
> > The new suspend/resume implementation, send pme turnoff message
> > in suspend, and send pme exit message in resume.
> >
> > Add a PME handler, to response PME & message interrupt.
> >
> > Change platform_driver->suspend/resume to syscore->suspend/resume.
> 
> Can you please first describe the problem you're trying to address?
> 
If we do nothing in suspend/resume, some platform PCIe ip-block can't guarantee
the link back to L0 state from sleep, then, when we read the EP device will hang. 
Only we send pme turnoff message in pci controller suspend, and send pme exit
message in resume, the link state will be normal.

When we send pme turnoff message in pci controller suspend, the links will into l2/l3
ready, then, host cannot communicate with ep device, but pci-driver will call back EP
device to save them state. So we need to change platform_driver->suspend/resume to
syscore->suspend/resume.

Thanks,
-Dongsheng