On Fri, 2012-12-07 at 00:47 +0800, Jiang Liu wrote: > On 12/05/2012 07:23 AM, Toshi Kani wrote: > > On Tue, 2012-12-04 at 17:16 +0800, Hanjun Guo wrote: > >> On 2012/12/4 8:10, Toshi Kani wrote: > >>> On Mon, 2012-12-03 at 12:25 +0800, Hanjun Guo wrote: > >>>> On 2012/11/30 6:27, Toshi Kani wrote: > >>>>> On Thu, 2012-11-29 at 12:48 +0800, Hanjun Guo wrote: > >>>>>> On 2012/11/29 2:41, Toshi Kani wrote: : > >>>> The ACPI specification provides _EDL method to > >>>> tell OS the eject device list, but still has no method to tell OS the add device > >>>> list now. > >>> > >>> Yes, but I do not think the OS needs special handling for add... > >> > >> Hmm, how about trigger a hot add operation by OS ? we have eject interface for OS, but > >> have no add interface now, do you think this feature is useful? If it is, I think OS > >> should analyze the dependency first and tell the user. > > > > The OS can eject an ACPI device because a target device is owned by the > > OS (i.e. enabled). For hot-add, a target ACPI device is not owned by > > the OS (i.e. disabled). Therefore, the OS is not supposed to change its > > state. So, I do not think we should support a hot-add operation by the > > OS. > We depends on the firmware to provide an interface to actually hot-add the device. > The sequence is: > 1) user trigger hot-add request by sysfs interfaces. > 2) hotplug framework validates conditions for hot-adding (dependency) > 3) hotplug framework invokes firmware interfaces to request a hot-adding operation. > 4) firmware sends an ACPI notificaitons after powering on/initializing the device > 5) OS adds the devices into running system. Interesting... In this sequence, I think FW must validate and check the dependency before sending a SCI. FW owns unassigned resources and is responsible for the procedure necessary to enable resources on the platform. Such steps are basically platform-specific. So, I do not think the common OS code should step into such business. Thanks, -Toshi -- 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
