From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [ACPI] PATCH-ACPI based CPU hotplug[2/6]-ACPI Eject interface support Date: Tue, 21 Sep 2004 22:10:07 -0500 Sender: linux-ia64-owner@vger.kernel.org Message-ID: <200409212210.07580.dtor_core@ameritech.net> References: <20040920092520.A14208@unix-os.sc.intel.com> <200409210051.36251.dtor_core@ameritech.net> <20040921145150.A27211@unix-os.sc.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20040921145150.A27211@unix-os.sc.intel.com> Content-Disposition: inline To: acpi-devel@lists.sourceforge.net, Keshavamurthy Anil S Cc: "Brown, Len" , LHNS list , Linux IA64 , Linux Kernel List-Id: linux-acpi@vger.kernel.org On Tuesday 21 September 2004 04:51 pm, Keshavamurthy Anil S wrote: > On Tue, Sep 21, 2004 at 12:51:36AM -0500, Dmitry Torokhov wrote: > > On Monday 20 September 2004 08:38 pm, Keshavamurthy Anil S wrote: > > > Currently I am handling both the surprise removal and the eject request in the same > > > way, i,e send the notification to the userland and the usermode agent scripts > > > is responsible for offlining of all the devices and then echoing onto eject file. > > > > > > > I actually think that on the highest level we should treat controlled and > > surprise ejects differently. With controlled ejects the system (kernel + > > userspace) can abort the sequence if something goes wrong while with surprise > > eject the device is physically gone. Even if driver refuses to detach or we > > have partition still mounted or something else if physical device is gone we > > don't have any choice except for trimming the tree and doing whatever we need > > to do. > > I agree, but when dealing with devices like CPU and Memory, not sure how the > rest of the Operating System handles surprise removal. For now I will go ahead and > add a PRINTK saying that BUS_CHECK(surprise removal request) was received in the > ACPI Processor and in the container driver, and when we hit that printk on a > real hardware, I believe it would be the right time then to see how the OS behaves > and do the right code then. For Now I will just go ahead and add a PRINTK. > Heh, I really don't expect the kernel to survive if somebody just yanks out a CPU without a warning, especially if the CPU is the last one :) I hand in mind devices like my port replicator that only has an additional network card and could survive surprise removal. > Let me know if this step by step approach is okay to you. It sure is, we can always adjust the process down the road. Thank you for your work! -- Dmitry