Date: Thu, 30 Mar 2006 19:40:24 GMT From: John Baldwin <jhb@freebsd.org> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/94939: [acpi] [patch] reboot(8) fails on IBM / Intel blades Message-ID: <200603301940.k2UJeO1I086485@freefall.freebsd.org>
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The following reply was made to PR kern/94939; it has been noted by GNATS. From: John Baldwin <jhb@freebsd.org> To: Nate Lawson <nate@root.org> Cc: "Devon H. O'Dell" <dodell@ixsystems.com>, bug-followup@freebsd.org Subject: Re: kern/94939: [acpi] [patch] reboot(8) fails on IBM / Intel blades Date: Thu, 30 Mar 2006 14:03:57 -0500 On Thursday 30 March 2006 13:23, Nate Lawson wrote: > John Baldwin wrote: > > On Tuesday 28 March 2006 02:22 pm, Devon H. O'Dell wrote: > >> On Tue, Mar 28, 2006 at 11:08:02AM -0800, Nate Lawson wrote: > >>> The system must reset immediately following the write to this register. > >>> OSPM assumes that the processor will not execute beyond the write > >>> instruction. OSPM should execute spin loops on the CPUs in the system > >>> following a write to this register. > >> My interpretation of this is ``don't do anything else after > >> the write to the register, because you can't expect to do > >> it.'' Since they say that the system ``must reset immediately > >> following the write'', it seems that this is implemented in > >> hardware, and we can't assume that we will be able to do > >> anything afterwards, anyway. > >> > >>> So I'm ok with the patch being committed if no other tasks need to > >>> happen after this shutdown handler is called. Also, all APs should be > >>> stopped before this happens and it should only occur once on the BSP. > >> I was curious if anything happens after this handler is > >> called -- if there is, we definitely need to move it back > >> to later in the process. Again, I put the code here because it > >> looked to me like the procedure already assumed nothing else > >> is happening, but it sounds like there are other procedures > >> that are in the call queue after this one. > > > > It really should be much later I think: in cpu_reset_real() as that > > is the only place that you know that the APs are stopped. > > I'm not near a BSD box today. Is there a simple, MI way of hooking > there that doesn't require ACPI compiled into the kernel? If it's a > simple matter of moving it to a different shutdown handler or adding a > way for acpi to conditionally override cpu_reset_real, that's ok with > me. I don't want acpi being partially merged into the main kernel. Not currently. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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