On Thursday, June 06, 2013 03:21:13 PM Greg Kroah-Hartman wrote: > 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. Well, thanks for looking. :-) This is not a big deal, because the module is loaded when present in the initramfs, but then I'm slightly concerned that people will complain "Oh, why do I need to have this module in my initramfs now and I didn't before?! It must be broken somehow!". And besides, I'm just curious what's going on here. :-) So far I have verified that topology_init() is executed before acpi_init() (which appears to be pure coincidence, but oh well), so even the *ordering* is the same as before. The only difference is that the device in question now has a driver bound to it and it didn't before (the driver was bound to something else). Hmm. I suspect udev just thinks "ok, I have found a driver for that device, so I don't need to look for one any more" and that's why it doesn't load acpi_cpufreq. If that's the case, is there any way to make it load all matching modules anyway? Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
