On Wednesday 25 June 2008 09:02:48 pm Zhao Yakui wrote: > On Wed, 2008-06-25 at 09:08 -0600, Bjorn Helgaas wrote: > > On Tuesday 24 June 2008 07:37:37 pm Zhao Yakui wrote: > > > On Tue, 2008-06-24 at 13:52 +0200, Vegard Nossum wrote: > > > > On 6/24/08, Ingo Molnar <mingo@xxxxxxx> wrote: > > > > > i havent seen the warning reappear with your fix after thousands of > > > > > bootups - so i guess we can consider it fixed. > > > > > > > > > > Len, please consider the patch below. (it's in tip/out-of-tree) > > > > > > > > No, please don't :-) > > > > > > > > It fixes your particular case (the acpi_rtc_init() hunk of the patch), > > > > but the acpi_walk_namespace() part should be changed to a WARN(). But > > > > that is likely to cause a lot of "spurious" reports, so the other acpi > > > > drivers should be fixed as well. > > > In fact this issue is related with the following factors: > > > a. when acpi is disabled, OS won't initialize the ACPI mutex, which > > > is accessed by many ACPI interface functions. For example: > > > acpi_walk_namespace, acpi_install_fixed_event_handler. > > > b. When acpi is disabled, some drivers will call the ACPI interface > > > functions. For example: The acpi_walk_namespace is called in > > > dock_init/bay_init. > > > > I think most current uses of acpi_walk_namespace() are indications > > that the ACPI or PNP core is missing something. > I don't think so. The acpi_walk_namespace is used to enumerate the ACPI > tree and execute some specific operations. For example: Add the device > notification function for some type of device; call the INI method for > all the device. There are exceptions, and obviously acpi_walk_namespace() will be needed some places. One example where I think acpi_walk_namespace() should not be used is to register notification functions for device addition/removal. I think the ACPI core should be handling those notify events and turning them into add()/remove() calls to the driver. > > In dock_init() and bay_init(), it's used to bind a driver to a > > device. I think it would be better if we could figure out how to > > use the usual acpi_bus_register_driver() interface. Actually, it > > looks like this is already 90% done: acpi_dock_match() does the > > same thing as is_dock(), so it looks like dock_init() could easily > > be converted to register as a driver for ACPI_DOCK_HID. > Maybe what you said is reasonable if the dock/bay device exists and is > added to Linux ACPI device tree. But if the status of bay/dock device > doesn't exist , it won't be added into the Linux ACPI device tree. In > such case the dock/bay driver won't be loaded for it. So it will be > reasonable to enumerate the acpi tree to install the notification > function for the dock device so that OS can receive the notification > event when the dock device is hotplugged. If the bay/dock device doesn't exist, we shouldn't need a driver for it. The normal scenario for non-ACPI drivers is that we load a driver when a device appears. That doesn't work very well in this case because the ACPI core is missing the "TBD: Handle device insertion/removal" stuff I mentioned earlier. I know it's not very useful for me to talk about this without providing any patches, so I'll shut up now. Bjorn -- 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
