Hi, Michael 在 2013-05-28二的 09:31 +0300，Michael S. Tsirkin写道： > On Tue, May 28, 2013 at 08:21:24AM +0800, li guang wrote: > > 在 2013-05-27一的 23:23 +0300，Michael S. Tsirkin写道： > > > On Mon, May 27, 2013 at 09:22:59AM +0800, li guang wrote: > > > > 在 2013-05-26日的 19:51 -0500，Anthony Liguori写道： > > > > > li guang <lig.f...@cn.fujitsu.com> writes: > > > > > > > > > > > 在 2013-05-24五的 14:45 +0300，Michael S. Tsirkin写道： > > > > > >> On Wed, May 22, 2013 at 11:46:33AM +0800, liguang wrote: > > > > > >> > These patches try to add ACPI Embedded Controller (EC), > > > > > >> > refer-to: > > > > > >> > ACPI SPEC v5 chapter 5 > > > > > >> > "ACPI Embedded Controller Interface Specification" > > > > > >> > > > > > > >> > EC is a standard ACPI device, it plays flexible roles, > > > > > >> > e.g. > > > > > >> > power controller, it can control power sequence for > > > > > >> > platform to enter or leave system state(0,1,3,4,5), > > > > > >> > it can controller CPU fan by the temperature of sensor. > > > > > >> > event carrier, it can pass events between platform > > > > > >> > and OS, so OS can execute _Qxx method which defined > > > > > >> > by yourself. > > > > > >> > > > > > > >> > So, I want to deliver CPU online/offline event between > > > > > >> > OS and QEMU for CPU hotplug feature, then we will don't > > > > > >> > need to "echo 1 > /sys/devices/system/cpu/cpu1/online" > > > > > >> > again after 'cpu-add'. > > > > > >> > > > > > > >> > patches for online/offline event handler of QEUM and > > > > > >> > linux kernel are writing, and will send once finished. > > > > > >> > > > > > > >> > since EC is a common device, so I send pathes separately. > > > > > >> > > > > > >> Do any non-linux guests support this device? > > > > > >> > > > > > > > > > > > > In fact, any OSes support ACPI will support this device. > > > > > > so, windows will. > > > > > > > > > > When you say "any OSes supporting ACPI" I think what you really mean > > > > > is > > > > > that we can provide bytecode that interacts with the embedded > > > > > controller. > > > > > > > > > > There is not explicit driver in Linux or Windows AFAIK. > > > > > > > > Hmm, yep, mostly there's no special driver for EC, > > > > because it is directly embedded in code for ACPI > > > > for linux kernel, it's drivers/acpi/ec.c > > > > > > > > > > > > > > I still don't get the point of this. We can make ACPI hotplug work > > > > > without introducing a new device like this. > > > > > > > > > > > > > when you 'cpu-add' a cpu, acpi driver for cpu will not > > > > trigger 'cpu_up' for linux kernel AFAIK, unless you add > > > > a user space program to listen it's uevent and tigger 'cpu_up'. > > > > > > > > and EC is not only for ACPI hotplug > > > > for example, the 'pvpanic', if there's a EC, > > > > we can pass pvpanic event by EC's ACPI space or Q-event, > > > > then we will not need this kind of special devices anymore. > > > > > > > > > > > > > > > > > So just to clarify: this patchset doesn't do anything useful > > > itself, > > > > the first patch is pure EC implementation which is useful. > > Sorry, I didn't mean to imply that this is not useful, > merely that it is not yet directly useful for users.
Yep, by now, of course, only 1 user, that's me. :-) > > > > it's some infrastructure that you want to build on > > > top of? > > > > Yes, I'd like to use EC as infrastructure for my further development. > > > > I (and apparently others in this thread) would like to know some more > about planned use for this code before deciding on inclusion. > OK, currently, I am using EC to pass cpu hotplug event between QEMU and linux kernel, and I'll post these patches later. then, I'll query usages like this in QEMU, and convert them to use EC's acpi approach if possible. Thanks!
