On Wed, 2009-07-15 at 08:37 +0800, Pavel Machek wrote:
> On Wed 2009-07-15 15:38:42, Zhang Rui wrote:
> >
> > i8042 controller support device async actions.
> >
> > If boot option "dev_async_action" is added,
> > i8042 controller and its child devices can be
> > suspended/resumed/shutdown asynchronously.
> >
> > Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> > ---
> > drivers/input/serio/i8042.c | 10 +++++++++-
> > 1 file changed, 9 insertions(+), 1 deletion(-)
> >
> > Index: linux-2.6/drivers/input/serio/i8042.c
> > ===================================================================
> > --- linux-2.6.orig/drivers/input/serio/i8042.c
> > +++ linux-2.6/drivers/input/serio/i8042.c
> > @@ -1284,14 +1284,21 @@ static int __init i8042_init(void)
> > goto err_unregister_driver;
> > }
> >
> > - err = platform_device_add(i8042_platform_device);
> > + err = dev_async_register(&i8042_platform_device->dev,
> > + DEV_ASYNC_SUSPEND | DEV_ASYNC_SHUTDOWN);
> > if (err)
> > goto err_free_device;
> >
> > + err = platform_device_add(i8042_platform_device);
> > + if (err)
> > + goto err_dev_async_unregister;
> > +
> > panic_blink = i8042_panic_blink;
> >
> > return 0;
> >
> > + err_dev_async_unregister:
> > + dev_async_unregister(&i8042_platform_device->dev);
>
>
> > err_free_device:
> > platform_device_put(i8042_platform_device);
> > err_unregister_driver:
> > @@ -1304,6 +1311,7 @@ static int __init i8042_init(void)
> >
> > static void __exit i8042_exit(void)
> > {
> > + dev_async_unregister(&i8042_platform_device->dev);
> > platform_device_unregister(i8042_platform_device);
> > platform_driver_unregister(&i8042_driver);
> > i8042_platform_exit();
>
> Could we get the core to do async_unregister during device_unregister?
>
yes, we can.
I think it's a little strange that drivers need to invoke
dev_async_register to register an async device group, but don't need to
call dev_async_unregister to unregister it.
> Or maybe better, just add flags during device_add?
>
Many devices don't know if they support async actions or not during
device initialization time, like PCI and ACPI devices.
If we want to create an async group for a PCI device, we have to call
dev_async_register in the specified PCI device driver, rather than in
the PCI bus scan stage.
thanks,
rui
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