Re: [linux-pm] [RFC,PATCHv3 0/3] sdhci runtime_pm implementation

From: Alan Stern
Date: Tue Mar 01 2011 - 14:57:10 EST


On Tue, 1 Mar 2011, Pierre Tardy wrote:

> On Tue, Mar 1, 2011 at 8:33 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> > On Tue, 1 Mar 2011, Pierre Tardy wrote:
> >
> >> Please find sdhci runtime_pm implementation.
> >>
> >> It uses clock gating fw as a tip to know when our chip is idle.
> >> It implements wake up from card insertion/removal.
> >>
> >> This is RFC, please dont merge yet. I really would like to have deep review
> >> from PCI linux-pm guys.
> >>
> >> Opens are:
> >>
> >> 1/ Not sure if the pci configs in the driver in rpm_suspend/resume flow
> >>  are not duplicate from what the core is doing.
> >
> > There may be one or two small errors.
> >
> >> 2/ Wakeup from D3hot: I cannot find any driver that is implementing it in current upstream,
> >
> > Other drivers do it, but they use PCI PME# instead of interrupts.
> Could you please elaborate?
> My understanding is that PCI PME will generate MSI, which translate in
> interrupt.

It depends on the platform. On systems with ACPI, PCI PME generates an
ACPI I/O event, which is handled by the ACPI and PM cores. It does not
invoke the device driver's interrupt handler.

Alan Stern

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