From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=51634 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1P8qD4-0000Mo-Pc for qemu-devel@nongnu.org; Thu, 21 Oct 2010 04:09:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1P8qD1-00020t-Ch for qemu-devel@nongnu.org; Thu, 21 Oct 2010 04:09:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40204) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1P8qD1-00020e-6a for qemu-devel@nongnu.org; Thu, 21 Oct 2010 04:09:11 -0400 Date: Thu, 21 Oct 2010 10:02:37 +0200 From: "Michael S. Tsirkin" Message-ID: <20101021080236.GA27985@redhat.com> References: <2f5cb93039ab90a7b267334dd5e2e94b7a550b9f.1287562197.git.yamahata@valinux.co.jp> <20101020100011.GE10783@redhat.com> <20101021034633.GA31309@valinux.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101021034633.GA31309@valinux.co.jp> Subject: [Qemu-devel] Re: [PATCH v6 07/12] pcie/hotplug: introduce pushing attention button command List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Isaku Yamahata Cc: skandasa@cisco.com, lmr@redhat.com, etmartin@cisco.com, wexu2@cisco.com, qemu-devel@nongnu.org, kraxel@redhat.com On Thu, Oct 21, 2010 at 12:46:33PM +0900, Isaku Yamahata wrote: > On Wed, Oct 20, 2010 at 12:00:11PM +0200, Michael S. Tsirkin wrote: > > On Wed, Oct 20, 2010 at 05:18:56PM +0900, Isaku Yamahata wrote: > > > glue pcie_push_attention_button command. > > > > > > Signed-off-by: Isaku Yamahata > > > > So as a high level command, I think we need to > > think about how to tie this into pci_add/pci_del. > > Right? > > Maybe or maybe not. > I'm not sure it's a good idea to tie it to pci_add/pci_del > in the first place. > The specification says only that pushing the button is just to > initiate the hot-plug operation. It means only a notification. > The spec says nothing about the concrete action from OS when > the button is pushed. It's up to OS. > > For example. > OS may start to probe the slot. > OS may start to quiescence the device. > OS is allowed to ignore the notification. > OS may propagate the notification to the management software, > and it would pop up the dialog to the user for further operation. > pci_add/pci_del really behave in the same way. There's no way to force the OS to respond. We only use ACPI for now, but for express I expect standard interfaces will work better long term. > > As a low level command, this is not really useful unless > > there is an event on LED status change and a way > > to get info on LED status. > > Right? > > No. Guest OS can provide users those infos, and Linux does > via sysfs. So there already is a way to know LED status. > This is the reason why LED status change event stuff has low > priority in my TODO list. But that's in the guest. -- MST