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    SubjectRe: [PATCH] Driver core: leave runtime PM enabled during system shutdown
    Date
    On Tuesday, December 06, 2011, Alan Stern wrote:
    > Disabling all runtime PM during system shutdown turns out not to be a
    > good idea, because some devices may need to be woken up from a
    > low-power state at that time.
    >
    > The whole point of disabling runtime PM for system shutdown was to
    > prevent untimely runtime-suspend method calls. This patch (as1504)
    > accomplishes the same result by incrementing the usage count for each
    > device and waiting for ongoing runtime-PM callbacks to finish. This
    > is what we already do during system suspend and hibernation, which
    > makes sense since the shutdown method is pretty much a legacy analog
    > of the pm->poweroff method.
    >
    > This fixes a regression on some OMAP systems.
    >
    > Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
    > Reported-by: NeilBrown <neilb@suse.de>
    > CC: Chen Peter-B29397 <B29397@freescale.com>

    Greg, do you have any objections against this patch and, if you don't,
    would you mind if I took it (it fixes one that went in through my tree).

    Thanks,
    Rafael


    > ---
    >
    > drivers/base/core.c | 6 ++++--
    > 1 file changed, 4 insertions(+), 2 deletions(-)
    >
    > Index: usb-3.2/drivers/base/core.c
    > ===================================================================
    > --- usb-3.2.orig/drivers/base/core.c
    > +++ usb-3.2/drivers/base/core.c
    > @@ -1743,8 +1743,10 @@ void device_shutdown(void)
    > */
    > list_del_init(&dev->kobj.entry);
    > spin_unlock(&devices_kset->list_lock);
    > - /* Disable all device's runtime power management */
    > - pm_runtime_disable(dev);
    > +
    > + /* Don't allow any more runtime suspends */
    > + pm_runtime_get_noresume(dev);
    > + pm_runtime_barrier(dev);
    >
    > if (dev->bus && dev->bus->shutdown) {
    > dev_dbg(dev, "shutdown\n");
    >
    > --
    > To unsubscribe from this list: send the line "unsubscribe linux-pm" in
    > the body of a message to majordomo@vger.kernel.org
    > More majordomo info at http://vger.kernel.org/majordomo-info.html
    >
    >



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