Re: [patch 1/11]avoid check _STA method

[Holger Macht <hmacht@suse.de>]

On Fri 26. Sep - 09:04:59, Shaohua Li wrote:
> On Thu, Sep 25, 2008 at 10:49:45PM +0800, Holger Macht wrote:
> > On Wed 24. Sep - 10:51:05, Shaohua Li wrote:
> > > On Mon, 2008-09-22 at 18:57 +0800, Holger Macht wrote:
> > > > On Thu 28. Aug - 10:02:03, Shaohua Li wrote:
> > > > > In some BIOSes, every _STA method call will send a notification again,
> > > > > this cause freeze. And in some BIOSes, it appears _STA should be called
> > > > > after _DCK. This tries to avoid calls _STA, and still keep the device
> > > > > present check.
> > > > > http://bugzilla.kernel.org/show_bug.cgi?id=10431
> > > >
> > > > Finally found some time to test this...
> > > >
> > > > >
> > > > > Signed-off-by: Shaohua Li <shaohua.li@intel.com>
> > > > > ---
> > > > >  drivers/acpi/dock.c |    5 ++++-
> > > > >  1 file changed, 4 insertions(+), 1 deletion(-)
> > > > >
> > > > > Index: linux/drivers/acpi/dock.c
> > > > > ===================================================================
> > > > > --- linux.orig/drivers/acpi/dock.c    2008-08-27 14:38:44.000000000 +0800
> > > > > +++ linux/drivers/acpi/dock.c 2008-08-28 09:33:02.000000000 +0800
> > > > > @@ -604,14 +604,17 @@ static int handle_eject_request(struct d
> > > > >  static void dock_notify(acpi_handle handle, u32 event, void *data)
> > > > >  {
> > > > >       struct dock_station *ds = data;
> > > > > +     struct acpi_device *tmp;
> > > > >
> > > > >       switch (event) {
> > > > >       case ACPI_NOTIFY_BUS_CHECK:
> > > > > -             if (!dock_in_progress(ds) && dock_present(ds)) {
> > > > > +             if (!dock_in_progress(ds) && acpi_bus_get_device(ds->handle,
> > > >
> > > > On the Thinkpad X60, when booting undocked, the first time I dock,
> > > > acpi_bus_get_device() returns 0, so hotplug is not performed
> > > > properly. Second time (undock->dock), it works.
> > > So the patch breaks your X60? acpi_bus_get_device() returns 0 means the
> > > device is already in ACPI device tree, but it shouldn't as it's not
> > > present.
> > 
> > Do you have a model number of a system which needs this patch? If so,
> > maybe I could get my hands on one to do some more testing...maybe finding
> > another solution...
> please see the bugzilla above. I haven't a system which requires this at hand.
> I'm quite strange why acpi_bus_get_device() returns 0 for a non-present device,
> maybe you can dig into this. Is it possible the BIOS wrongly reported device
> status?

No, it was a bug in the acpi subsystem:

commit 39a0ad871000d2a016a4fa113a6e53d22aabf25d
Author: Zhao Yakui <yakui.zhao@intel.com>
Date:   Mon Aug 11 13:40:22 2008 +0800

    ACPI : Load device driver according to the status of acpi device


Regards,
	Holger