On Tue, 28 May 2013 14:40:30 +0800 li guang <lig.f...@cn.fujitsu.com> wrote:
> 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. When I see these patches for qemu/seebios/kernel, I probably would be able to comment on them. But right now I don't see benefits in switching CPU hot-plug to EC. > > Thanks! > > > >
