Re: [PATCH 01/10] ACPI: support acpi_device_ops .notify methods

[Thomas Renninger <trenn@suse.de>]

On Friday 03 April 2009 02:23:16 Yasunori Goto wrote:
> > On Thursday 02 April 2009 07:56:28 am Thomas Renninger wrote:
> > > On Monday 30 March 2009 19:48:13 Bjorn Helgaas wrote:
> > > > This patch adds support for ACPI device driver .notify() methods.  If
> > > > such a method is present, Linux/ACPI installs a handler for device
> > > > notifications (but not for system notifications such as Bus Check,
> > > > Device Check, etc).  When a device notification occurs, Linux/ACPI
> > > > passes it on to the driver's .notify() method.
> > > I sent more or less the same some years ago.
> > > Thanks a lot for finally cleaning this up!
> > 
> > Hi Thomas,
> > 
> > Oh, sorry, I didn't know that, or I would have given you some credit :-)
> > In fact, if you have a URL, I'll add a pointer to the changelog.  I
> > always like to leave breadcrumbs to help future research.
> > 
> > > > Several drivers install their own handlers for system Bus Check and
> > > > Device Check notifications so they can support hot-plug.  This patch
> > > > doesn't affect that usage.
> > > Getting rid of these will be the tricky part.
> > > When I looked at it start/stop already was defined, but nobody used it.
> > > IMO start/stop is not needed and hotplug capable device drivers can
> > > handle things themselves in the relevant notify case.
> > 
> > I'd really like to get rid of the bus/device check notification stuff
> > in the drivers eventually.  IMHO, the core Linux/ACPI code should
> > field those notifications and just call the driver .add() and .remove()
> > methods as necessary.
> > 
> > But you're right, it's going to be quite tricky.  I'm looking at getting
> > rid of .start() right now, because that's a major complication.  The
> > biggest user looks like acpiphp, and that is going to be a mess to
> > straighten out.
> > 
> > > I remember these two guys helped me testing on memory hotplug.
> > > They only had a simulator, but might want to give the latest kernel a try if
> > > you come to clean up acpi_memhotplug.c:
> > > kamezawa.hiroyu@jp.fujitsu.com
> > > Yasunori Goto <y-goto@jp.fujitsu.com>
> 
> I can use real machine which can memory hotplug.
> In our case, notify method is called for container device (NUMA node),
> and memory and processor devices are added under acpi_bus_scan().
> 
> I'll book it to test this patch in next week.
> It must be good test. :-)

Better wait a bit or ask Bjorn.
I expect this is only the beginning of his cleanups and the tricky
parts will still come.

Thanks,

      Thomas