diff mbox

ACPI / scan: Always call acpi_bus_scan() for bus check notifications

Message ID 6189099.QeK4PsCIFb@vostro.rjw.lan (mailing list archive)
State Accepted, archived
Headers show

Commit Message

Rafael Wysocki July 10, 2013, 10:45 p.m. UTC 
On Wednesday, July 10, 2013 02:11:05 AM Rafael J. Wysocki wrote:
> On Tuesday, July 09, 2013 01:32:42 PM Toshi Kani wrote:
> > On Mon, 2013-07-08 at 02:10 +0200, Rafael J. Wysocki wrote:
> > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > 
> > > An ACPI_NOTIFY_BUS_CHECK notification means that we should scan the
> > > entire namespace starting from the given handle even if the device
> > > represented by that handle is present (other devices below it may
> > > just have been added).
> > > 
> > > For this reason, modify acpi_scan_bus_device_check() to always run
> > > acpi_bus_scan() if the notification being handled is of type
> > > ACPI_NOTIFY_BUS_CHECK.
> > > 
> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > Cc: 3.10+ <stable@vger.kernel.org>
> > 
> > Acked-by: Toshi Kani <toshi.kani@hp.com>
> > 
> > But, I think we need the additional patch below.
> 
> Yes, I think you're right.

That said I'd prefer to put the check into acpi_bus_device_attach() like in
the appended patch.

Thanks,
Rafael


---
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Subject: ACPI / scan: Do not try to attach scan handlers to devices having them

In acpi_bus_device_attach(), if there is an ACPI device object
for the given handle and that device object has a scan handler
attached to it already, there's nothing more to do for that handle
and the function should just return success immediately.  Make
that happen.

Reported-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/scan.c |    3 +++
 1 file changed, 3 insertions(+)


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Comments

Toshi Kani July 10, 2013, 11:48 p.m. UTC | #1 
On Thu, 2013-07-11 at 00:45 +0200, Rafael J. Wysocki wrote:
> On Wednesday, July 10, 2013 02:11:05 AM Rafael J. Wysocki wrote:
> > On Tuesday, July 09, 2013 01:32:42 PM Toshi Kani wrote:
> > > On Mon, 2013-07-08 at 02:10 +0200, Rafael J. Wysocki wrote:
> > > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > > 
> > > > An ACPI_NOTIFY_BUS_CHECK notification means that we should scan the
> > > > entire namespace starting from the given handle even if the device
> > > > represented by that handle is present (other devices below it may
> > > > just have been added).
> > > > 
> > > > For this reason, modify acpi_scan_bus_device_check() to always run
> > > > acpi_bus_scan() if the notification being handled is of type
> > > > ACPI_NOTIFY_BUS_CHECK.
> > > > 
> > > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > > Cc: 3.10+ <stable@vger.kernel.org>
> > > 
> > > Acked-by: Toshi Kani <toshi.kani@hp.com>
> > > 
> > > But, I think we need the additional patch below.
> > 
> > Yes, I think you're right.
> 
> That said I'd prefer to put the check into acpi_bus_device_attach() like in
> the appended patch.

That's fine by me.  

Acked-by: Toshi Kani <toshi.kani@hp.com>

Just a minor point, though.  Isn't it a bit inconsistent with
device_attach(), which checks dev->driver inside the function?  That
said, I am OK with either way.

Thanks,
-Toshi


> 
> Thanks,
> Rafael
> 
> 
> ---
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Subject: ACPI / scan: Do not try to attach scan handlers to devices having them
> 
> In acpi_bus_device_attach(), if there is an ACPI device object
> for the given handle and that device object has a scan handler
> attached to it already, there's nothing more to do for that handle
> and the function should just return success immediately.  Make
> that happen.
> 
> Reported-by: Toshi Kani <toshi.kani@hp.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>  drivers/acpi/scan.c |    3 +++
>  1 file changed, 3 insertions(+)
> 
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -1984,6 +1984,9 @@ static acpi_status acpi_bus_device_attac
>  	if (acpi_bus_get_device(handle, &device))
>  		return AE_CTRL_DEPTH;
>  
> +	if (device->handler)
> +		return AE_OK;
> +
>  	ret = acpi_scan_attach_handler(device);
>  	if (ret)
>  		return ret > 0 ? AE_OK : AE_CTRL_DEPTH;
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html


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Rafael Wysocki July 11, 2013, 12:39 a.m. UTC | #2 
On Wednesday, July 10, 2013 05:48:26 PM Toshi Kani wrote:
> On Thu, 2013-07-11 at 00:45 +0200, Rafael J. Wysocki wrote:
> > On Wednesday, July 10, 2013 02:11:05 AM Rafael J. Wysocki wrote:
> > > On Tuesday, July 09, 2013 01:32:42 PM Toshi Kani wrote:
> > > > On Mon, 2013-07-08 at 02:10 +0200, Rafael J. Wysocki wrote:
> > > > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > > > 
> > > > > An ACPI_NOTIFY_BUS_CHECK notification means that we should scan the
> > > > > entire namespace starting from the given handle even if the device
> > > > > represented by that handle is present (other devices below it may
> > > > > just have been added).
> > > > > 
> > > > > For this reason, modify acpi_scan_bus_device_check() to always run
> > > > > acpi_bus_scan() if the notification being handled is of type
> > > > > ACPI_NOTIFY_BUS_CHECK.
> > > > > 
> > > > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > > > Cc: 3.10+ <stable@vger.kernel.org>
> > > > 
> > > > Acked-by: Toshi Kani <toshi.kani@hp.com>
> > > > 
> > > > But, I think we need the additional patch below.
> > > 
> > > Yes, I think you're right.
> > 
> > That said I'd prefer to put the check into acpi_bus_device_attach() like in
> > the appended patch.
> 
> That's fine by me.  
> 
> Acked-by: Toshi Kani <toshi.kani@hp.com>
> 
> Just a minor point, though.  Isn't it a bit inconsistent with
> device_attach(), which checks dev->driver inside the function?

Well, device_attach() may be called from different places while this is
the only place where acpi_scan_attach_handler() is called.

The check in acpi_bus_device_attach() is easier to follow to me, because
it clearly means "we don't need to do anything more if there's a handler",
while the check in acpi_scan_attach_handler() makes you wonder "why do we
need to return 1 in that case?" and then you need to go to the caller and
look at the check of the return value to see "ah, because we don't want
that device_attach() to be called then!".

> That said, I am OK with either way.

Cool. :-)

Thanks,
Rafael


> > ---
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > Subject: ACPI / scan: Do not try to attach scan handlers to devices having them
> > 
> > In acpi_bus_device_attach(), if there is an ACPI device object
> > for the given handle and that device object has a scan handler
> > attached to it already, there's nothing more to do for that handle
> > and the function should just return success immediately.  Make
> > that happen.
> > 
> > Reported-by: Toshi Kani <toshi.kani@hp.com>
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > ---
> >  drivers/acpi/scan.c |    3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > Index: linux-pm/drivers/acpi/scan.c
> > ===================================================================
> > --- linux-pm.orig/drivers/acpi/scan.c
> > +++ linux-pm/drivers/acpi/scan.c
> > @@ -1984,6 +1984,9 @@ static acpi_status acpi_bus_device_attac
> >  	if (acpi_bus_get_device(handle, &device))
> >  		return AE_CTRL_DEPTH;
> >  
> > +	if (device->handler)
> > +		return AE_OK;
> > +
> >  	ret = acpi_scan_attach_handler(device);
> >  	if (ret)
> >  		return ret > 0 ? AE_OK : AE_CTRL_DEPTH;
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
Toshi Kani July 11, 2013, 4:15 p.m. UTC | #3 
On Thu, 2013-07-11 at 02:39 +0200, Rafael J. Wysocki wrote:
> On Wednesday, July 10, 2013 05:48:26 PM Toshi Kani wrote:
> > On Thu, 2013-07-11 at 00:45 +0200, Rafael J. Wysocki wrote:
> > > On Wednesday, July 10, 2013 02:11:05 AM Rafael J. Wysocki wrote:
> > > > On Tuesday, July 09, 2013 01:32:42 PM Toshi Kani wrote:
> > > > > On Mon, 2013-07-08 at 02:10 +0200, Rafael J. Wysocki wrote:
> > > > > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > > > > 
> > > > > > An ACPI_NOTIFY_BUS_CHECK notification means that we should scan the
> > > > > > entire namespace starting from the given handle even if the device
> > > > > > represented by that handle is present (other devices below it may
> > > > > > just have been added).
> > > > > > 
> > > > > > For this reason, modify acpi_scan_bus_device_check() to always run
> > > > > > acpi_bus_scan() if the notification being handled is of type
> > > > > > ACPI_NOTIFY_BUS_CHECK.
> > > > > > 
> > > > > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > > > > Cc: 3.10+ <stable@vger.kernel.org>
> > > > > 
> > > > > Acked-by: Toshi Kani <toshi.kani@hp.com>
> > > > > 
> > > > > But, I think we need the additional patch below.
> > > > 
> > > > Yes, I think you're right.
> > > 
> > > That said I'd prefer to put the check into acpi_bus_device_attach() like in
> > > the appended patch.
> > 
> > That's fine by me.  
> > 
> > Acked-by: Toshi Kani <toshi.kani@hp.com>
> > 
> > Just a minor point, though.  Isn't it a bit inconsistent with
> > device_attach(), which checks dev->driver inside the function?
> 
> Well, device_attach() may be called from different places while this is
> the only place where acpi_scan_attach_handler() is called.
> 
> The check in acpi_bus_device_attach() is easier to follow to me, because
> it clearly means "we don't need to do anything more if there's a handler",
> while the check in acpi_scan_attach_handler() makes you wonder "why do we
> need to return 1 in that case?" and then you need to go to the caller and
> look at the check of the return value to see "ah, because we don't want
> that device_attach() to be called then!".

Sounds good to me.

Thanks,
-Toshi


> 
> > That said, I am OK with either way.
> 
> Cool. :-)
> 
> Thanks,
> Rafael
> 
> 
> > > ---
> > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > Subject: ACPI / scan: Do not try to attach scan handlers to devices having them
> > > 
> > > In acpi_bus_device_attach(), if there is an ACPI device object
> > > for the given handle and that device object has a scan handler
> > > attached to it already, there's nothing more to do for that handle
> > > and the function should just return success immediately.  Make
> > > that happen.
> > > 
> > > Reported-by: Toshi Kani <toshi.kani@hp.com>
> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > ---
> > >  drivers/acpi/scan.c |    3 +++
> > >  1 file changed, 3 insertions(+)
> > > 
> > > Index: linux-pm/drivers/acpi/scan.c
> > > ===================================================================
> > > --- linux-pm.orig/drivers/acpi/scan.c
> > > +++ linux-pm/drivers/acpi/scan.c
> > > @@ -1984,6 +1984,9 @@ static acpi_status acpi_bus_device_attac
> > >  	if (acpi_bus_get_device(handle, &device))
> > >  		return AE_CTRL_DEPTH;
> > >  
> > > +	if (device->handler)
> > > +		return AE_OK;
> > > +
> > >  	ret = acpi_scan_attach_handler(device);
> > >  	if (ret)
> > >  		return ret > 0 ? AE_OK : AE_CTRL_DEPTH;
> > > 
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> > > the body of a message to majordomo@vger.kernel.org
> > > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > 
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html


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diff mbox

Patch

Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -1984,6 +1984,9 @@  static acpi_status acpi_bus_device_attac
 	if (acpi_bus_get_device(handle, &device))
 		return AE_CTRL_DEPTH;
 
+	if (device->handler)
+		return AE_OK;
+
 	ret = acpi_scan_attach_handler(device);
 	if (ret)
 		return ret > 0 ? AE_OK : AE_CTRL_DEPTH;