Re: Q: acpi-cpufreq module auto-loading after processor driver change

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Fri, Jun 07, 2013 at 12:13:58AM +0200, Rafael J. Wysocki wrote:
> On Thursday, June 06, 2013 11:51:54 PM Rafael J. Wysocki wrote:
> > On Thursday, June 06, 2013 01:24:19 PM Greg Kroah-Hartman wrote:
> > > On Thu, May 30, 2013 at 11:38:37PM +0200, Rafael J. Wysocki wrote:
> > > > Hi Greg,
> > > > 
> > > > I've noticed during recent testing that with this commit applied:
> > > > 
> > > > http://git.kernel.org/cgit/linux/kernel/git/rafael/linux-pm.git/commit/?h=acpi-hotplug&id=ac212b6980d8d5eda705864fc5a8ecddc6d6eacc
> > > > 
> > > > on my openSUSE (and Tubmbleweed) installations I need to modify
> > > > /etc/sysconfig/kernel to make mkinitrd put the acpi-cpufreq module into the
> > > > initramfs or otherwise it won't be loaded automatically.
> > > > 
> > > > I think I understand why it needs to be present in the initramfs along the
> > > > processor module for the automatic loading to work (acpi_processor_load_module()
> > > > seems to need that), but before the above commit it wasn't necessary to make
> > > > any changes to /etc/sysconfig/kernel and acpi-cpufreq was loaded automatically
> > > > anyway.
> > > > 
> > > > Unfortunately, my experience with udev and related things is kind of limited
> > > > and I have no idea what exactly makes the difference.  Can you please have a
> > > > look and help me understand that?
> > > 
> > > Don't you need a MODULE_DEVICE_TABLE() macro in that module somewhere so
> > > that udev and the like know to load it when it sees the hardware?
> > 
> > Well, that was my first thought about that, but there is one already and my
> > commit hasn't changed it. :-)
> 
> My understanding of this is that on x86 (which is the case here)
> topology_init() calls arch_register_cpu() for all available CPUs which
> calls register_cpu() and that causes the uevent to be emitted through
> device_register().  But then, the commit above doesn't change that (at least
> I don't see how).

At first glance, I don't see how either, sorry.

greg k-h