On Tuesday 18 August 2009, Rafael J. Wysocki wrote:
> On Tuesday 18 August 2009, Zhang Rui wrote:
> > On Mon, 2009-08-17 at 08:15 +0800, Rafael J. Wysocki wrote:
> > > On Wednesday 12 August 2009, Rafael J. Wysocki wrote:
> > > > Hi,
> > > >
> > > > The following patches introduce a mechanism allowing us to execute device
> > > > drivers' suspend and resume callbacks asynchronously during system sleep
> > > > transitions, such as suspend to RAM. The idea is explained in the [1/1] patch
> > > > message.
> > >
> > > Changes:
> > >
> > > * Added [1/7] that fixes kerneldoc comments in drivers/base/power/main.c
> > > (this is a 2.6.32 candidate).
> > >
> > > * Added [2/7] adding a framework for representing PM link (idea described
> > > in the patch message).
> > >
> > > * [3/7] is the async resume patch (idea described in the patch message).
> > >
> > > * [4/7] is the async suspend patch.
> > >
> > > * [5/7] - [7/7] set async_suspend for devices in a few selected subsystems.
> > >
> > > The patches have been tested on HP nx6325.
> > >
> > I tried this patch set and it does work. :)
> > But unfortunately it doesn't save too much time.
> >
> > I still think that the child device should inherit its parent's
> > async_suspend flag to do the asynchronous resume more efficiently.
> >
> > or at least we should provide such an interface
> > in drivers/base/power/common.c, so that device can tell the device core
> > to inherit this flag if there is no off-tree dependency.
>
> Well, I'd prefer to identify all of the off-tree dependencies that have to be
> taken into account and handle all devices asynchronously.
Anyway, I have tested the appended patch on top of [1/7]-[7/7] and my test box
appears to work fine with it, although it doesn't work in the "async for all"
case.
I guess the next step will be to see which devices are not handled
asynchronously with the patch below and try to figure out which of them
break(s) things.
Thanks,
Rafael
---
drivers/base/power/common.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
Index: linux-2.6/drivers/base/power/common.c
===================================================================
--- linux-2.6.orig/drivers/base/power/common.c
+++ linux-2.6/drivers/base/power/common.c
@@ -32,7 +32,11 @@ void device_pm_add(struct device *dev)
pr_debug("PM: Adding info for %s:%s\n",
dev->bus ? dev->bus->name : "No Bus",
kobject_name(&dev->kobj));
- pm_link_add(dev, dev->parent);
+ if (dev->parent) {
+ pm_link_add(dev, dev->parent);
+ if (dev->parent->power.async_suspend)
+ dev->power.async_suspend = true;
+ }
device_pm_list_add(dev);
}
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