From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Toshi Kani <toshi.kani@hp.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
isimatu.yasuaki@jp.fujitsu.com,
vasilis.liaskovitis@profitbricks.com, Len Brown <lenb@kernel.org>
Subject: Re: [PATCH 4/4] ACPI / processor: Use common hotplug infrastructure
Date: Fri, 03 May 2013 21:31:50 +0200 [thread overview]
Message-ID: <2355471.VAFinTCtRm@vostro.rjw.lan> (raw)
In-Reply-To: <1367605674.16154.198.camel@misato.fc.hp.com>
On Friday, May 03, 2013 12:27:54 PM Toshi Kani wrote:
> On Fri, 2013-05-03 at 14:05 +0200, Rafael J. Wysocki wrote:
> > On Thursday, May 02, 2013 05:20:12 PM Toshi Kani wrote:
> > > On Thu, 2013-05-02 at 14:31 +0200, Rafael J. Wysocki wrote:
> > > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> :
> > > > Index: linux-pm/drivers/base/cpu.c
> > > > ===================================================================
> > > > --- linux-pm.orig/drivers/base/cpu.c
> > > > +++ linux-pm/drivers/base/cpu.c
> > > > @@ -13,11 +13,21 @@
> > > > #include <linux/gfp.h>
> > > > #include <linux/slab.h>
> > > > #include <linux/percpu.h>
> > > > +#include <linux/acpi.h>
> > > >
> > > > #include "base.h"
> > > >
> > > > static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
> > > >
> > > > +static int cpu_subsys_match(struct device *dev, struct device_driver *drv)
> > > > +{
> > > > + /* ACPI style match is the only one that may succeed. */
> > > > + if (acpi_driver_match_device(dev, drv))
> > >
> > > Can you explain why this change is needed?
> >
> > This is the mechanism by which the driver core determines which driver to use
> > with a processor device passed to device_attach().
> >
> > Basically, it walks the list of drivers whose bus type is cpu_subsys and
> > calls cpu_subsys->match(), which points to cpu_subsys_match(), for the device
> > and each of the drivers. The result of that tell is whether or not to use
> > the given driver with the device.
> >
> > Now, acpi_driver_match_device() returns 'true' if (a) the device has an ACPI
> > handle and (b) at least one of the IDs of the struct acpi_device associated
> > with that handle is in the driver's .acpi_match_table table. Since the ACPI
> > processor's .acpi_match_table contains the same set of IDs as the table
> > of device IDs of processor_handler, this guarantees that the ACPI processor
> > driver will be used for the devices prepared by acpi_processor_add().
> >
> > What it boils down to is that acpi_processor_start() is going to be called
> > for every device whose ACPI handle is populated by acpi_processor_add().
> >
> > > Do CPU devices still behave the same on non-ACPI systems?
> >
> > Yes, they do. The whole driver matching/binding is irrelevant to them, because
> > the ACPI processor driver is the only one registering itself under cpu_subsys.
>
> Thanks for the detailed explanation! I missed that the new processor
> driver is registered to cpu_subsys. I now see what you did. This is
> clever.
Well, thanks! :-)
> One minor comment.
>
> +static __cpuinit int __acpi_processor_start(struct acpi_device *device)
> > {
> > - struct acpi_device *device = per_cpu(processor_device_array,
> pr->id);
> > + struct acpi_processor *pr = acpi_driver_data(device);
> > + acpi_status status;
> > int result = 0;
> >
> > + if (!pr)
> > + return -ENODEV;
> > +
> > + if (pr->flags.need_hotplug_init)
> > + return 0;
> > +
>
> I felt the name of "need_hotplug_init" is a bit misleading since the
> func actually skips when the need-flag is set. It may be nice to rename
> it to defer_online_init, offline or something like that.
I just wanted to avoid making too many non-essential changes in one patch.
We can change the name of that field at any time later.
> Otherwise the changes look very good.
>
> Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Thank you!
Rafael
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
next prev parent reply other threads:[~2013-05-03 19:23 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-29 12:23 [PATCH 0/3 RFC] Driver core / ACPI: Add offline/online for graceful hot-removal of devices Rafael J. Wysocki
2013-04-29 12:26 ` [PATCH 1/3 RFC] Driver core: Add offline/online device operations Rafael J. Wysocki
2013-04-29 23:10 ` Greg Kroah-Hartman
2013-04-30 11:59 ` Rafael J. Wysocki
2013-04-30 15:32 ` Greg Kroah-Hartman
2013-04-30 20:05 ` Rafael J. Wysocki
2013-04-30 23:38 ` Toshi Kani
2013-05-02 0:58 ` Rafael J. Wysocki
2013-05-02 23:29 ` Toshi Kani
2013-05-03 11:48 ` Rafael J. Wysocki
2013-04-29 12:28 ` [PATCH 2/3 RFC] Driver core: Use generic offline/online for CPU offline/online Rafael J. Wysocki
2013-04-29 23:11 ` Greg Kroah-Hartman
2013-04-30 12:01 ` Rafael J. Wysocki
2013-04-30 15:27 ` Greg Kroah-Hartman
2013-04-30 20:06 ` Rafael J. Wysocki
2013-04-30 23:42 ` Toshi Kani
2013-05-01 14:49 ` Rafael J. Wysocki
2013-05-01 20:07 ` Toshi Kani
2013-05-02 0:26 ` Rafael J. Wysocki
2013-04-29 12:29 ` [PATCH 3/3 RFC] ACPI / hotplug: Use device offline/online for graceful hot-removal Rafael J. Wysocki
2013-04-30 23:49 ` Toshi Kani
2013-05-01 15:05 ` Rafael J. Wysocki
2013-05-01 20:20 ` Toshi Kani
2013-05-02 0:53 ` Rafael J. Wysocki
2013-05-02 12:26 ` [PATCH 0/4] Driver core / ACPI: Add offline/online for graceful hot-removal of devices Rafael J. Wysocki
2013-05-02 12:27 ` [PATCH 1/4] Driver core: Add offline/online device operations Rafael J. Wysocki
2013-05-02 13:57 ` Greg Kroah-Hartman
2013-05-02 23:11 ` Toshi Kani
2013-05-02 23:36 ` Rafael J. Wysocki
2013-05-02 23:23 ` Toshi Kani
2013-05-02 12:28 ` [PATCH 2/4] Driver core: Use generic offline/online for CPU offline/online Rafael J. Wysocki
2013-05-02 13:57 ` Greg Kroah-Hartman
2013-05-02 12:29 ` [PATCH 3/4] ACPI / hotplug: Use device offline/online for graceful hot-removal Rafael J. Wysocki
2013-05-02 12:31 ` [PATCH 4/4] ACPI / processor: Use common hotplug infrastructure Rafael J. Wysocki
2013-05-02 13:59 ` Greg Kroah-Hartman
2013-05-02 23:20 ` Toshi Kani
2013-05-03 12:05 ` Rafael J. Wysocki
2013-05-03 12:21 ` Rafael J. Wysocki
2013-05-03 18:27 ` Toshi Kani
2013-05-03 19:31 ` Rafael J. Wysocki [this message]
2013-05-03 19:34 ` Toshi Kani
2013-05-04 1:01 ` [PATCH 0/3 RFC] Driver core: Add offline/online callbacks for memory_subsys Rafael J. Wysocki
2013-05-04 1:03 ` [PATCH 1/3 RFC] ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes Rafael J. Wysocki
2013-05-04 1:04 ` [PATCH 2/3 RFC] Driver core: Introduce types of device "online" Rafael J. Wysocki
2013-05-04 1:06 ` [PATCH 3/3 RFC] Driver core: Introduce offline/online callbacks for memory blocks Rafael J. Wysocki
2013-05-04 11:11 ` [PATCH 0/2 v2, RFC] Driver core: Add offline/online callbacks for memory_subsys Rafael J. Wysocki
2013-05-04 11:12 ` [PATCH 1/2 v2, RFC] ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes Rafael J. Wysocki
2013-05-21 6:50 ` Tang Chen
2013-05-04 11:21 ` [PATCH 2/2 v2, RFC] Driver core: Introduce offline/online callbacks for memory blocks Rafael J. Wysocki
2013-05-06 16:28 ` Vasilis Liaskovitis
2013-05-07 0:59 ` Rafael J. Wysocki
2013-05-07 10:59 ` Vasilis Liaskovitis
2013-05-07 12:11 ` Rafael J. Wysocki
2013-05-07 21:03 ` Toshi Kani
2013-05-07 22:10 ` Rafael J. Wysocki
2013-05-07 22:45 ` Toshi Kani
2013-05-07 23:17 ` Rafael J. Wysocki
2013-05-07 23:59 ` Toshi Kani
2013-05-08 0:24 ` Rafael J. Wysocki
2013-05-08 0:37 ` Toshi Kani
2013-05-08 11:53 ` Rafael J. Wysocki
2013-05-08 14:38 ` Toshi Kani
2013-05-06 17:20 ` Greg Kroah-Hartman
2013-05-06 19:46 ` Rafael J. Wysocki
2013-05-21 6:37 ` Tang Chen
2013-05-21 11:15 ` Rafael J. Wysocki
2013-05-22 4:45 ` Tang Chen
2013-05-22 10:42 ` Rafael J. Wysocki
2013-05-22 22:06 ` [PATCH] Driver core / memory: Simplify __memory_block_change_state() Rafael J. Wysocki
2013-05-22 22:14 ` Greg Kroah-Hartman
2013-05-22 23:29 ` Rafael J. Wysocki
2013-05-23 4:37 ` Tang Chen
2013-05-06 10:48 ` [PATCH 0/2 v2, RFC] Driver core: Add offline/online callbacks for memory_subsys Rafael J. Wysocki
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