diff mbox

ACPI / scan: Allow ACPI drivers to bind to PNP device objects

Message ID 5487060.QsgluucUH4@vostro.rjw.lan (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Rafael J. Wysocki Aug. 21, 2014, 4:04 a.m. UTC
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

We generally don't allow ACPI drivers to bind to ACPI device objects
that companion "physical" device objects are created for to avoid
situations in which two different drivers may attempt to handle one
device at the same time.  Recent ACPI device enumeration rework
extended that approach to ACPI PNP devices by starting to use a scan
handler for enumerating them.  However, we previously allowed ACPI
drivers to bind to ACPI device objects with existing PNP device
companions and changing that led to functional regressions on some
systems.

For this reason, add a special check for PNP devices in
acpi_device_probe() so that ACPI drivers can bind to ACPI device
objects having existing PNP device companions as before.

Fixes: eec15edbb0e1 (ACPI / PNP: use device ID list for PNPACPI device enumeration)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=81511
Link: https://bugzilla.kernel.org/show_bug.cgi?id=81971
Reported-and-tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Reported-and-tested-by: Dirk Griesbach <spamthis@freenet.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/acpi_pnp.c |    5 +++++
 drivers/acpi/internal.h |    1 +
 drivers/acpi/scan.c     |    2 +-
 3 files changed, 7 insertions(+), 1 deletion(-)

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Comments

Zhang Rui Aug. 24, 2014, 7:06 a.m. UTC | #1
On Thu, 2014-08-21 at 06:04 +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> We generally don't allow ACPI drivers to bind to ACPI device objects
> that companion "physical" device objects are created for to avoid
> situations in which two different drivers may attempt to handle one
> device at the same time.  Recent ACPI device enumeration rework
> extended that approach to ACPI PNP devices by starting to use a scan
> handler for enumerating them.  However, we previously allowed ACPI
> drivers to bind to ACPI device objects with existing PNP device
> companions and changing that led to functional regressions on some
> systems.
> 
> For this reason, add a special check for PNP devices in
> acpi_device_probe() so that ACPI drivers can bind to ACPI device
> objects having existing PNP device companions as before.
> 
> Fixes: eec15edbb0e1 (ACPI / PNP: use device ID list for PNPACPI device enumeration)
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=81511
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=81971
> Reported-and-tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
> Reported-and-tested-by: Dirk Griesbach <spamthis@freenet.de>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>  drivers/acpi/acpi_pnp.c |    5 +++++
>  drivers/acpi/internal.h |    1 +
>  drivers/acpi/scan.c     |    2 +-
>  3 files changed, 7 insertions(+), 1 deletion(-)
> 
> Index: linux-pm/drivers/acpi/acpi_pnp.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/acpi_pnp.c
> +++ linux-pm/drivers/acpi/acpi_pnp.c
> @@ -396,3 +396,8 @@ void __init acpi_pnp_init(void)
>  {
>  	acpi_scan_add_handler(&acpi_pnp_handler);
>  }
> +
> +bool is_acpi_pnp_device(struct acpi_device *adev)
> +{
> +	return adev->handler == &acpi_pnp_handler;
> +}

can we reuse acpi_is_pnp_device()?
The only difference is that acpi_is_pnp_device() returns true for
RTC_CMOS devices, which is not a problem IMO because RTC CMOS devices
have PNP driver only.

thanks,
rui

> Index: linux-pm/drivers/acpi/internal.h
> ===================================================================
> --- linux-pm.orig/drivers/acpi/internal.h
> +++ linux-pm/drivers/acpi/internal.h
> @@ -86,6 +86,7 @@ void acpi_device_add_finalize(struct acp
>  void acpi_free_pnp_ids(struct acpi_device_pnp *pnp);
>  bool acpi_device_is_present(struct acpi_device *adev);
>  bool acpi_device_is_battery(struct acpi_device *adev);
> +bool is_acpi_pnp_device(struct acpi_device *adev);
>  
>  /* --------------------------------------------------------------------------
>                                    Power Resource
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -975,7 +975,7 @@ static int acpi_device_probe(struct devi
>  	struct acpi_driver *acpi_drv = to_acpi_driver(dev->driver);
>  	int ret;
>  
> -	if (acpi_dev->handler)
> +	if (acpi_dev->handler && !is_acpi_pnp_device(acpi_dev))
>  		return -EINVAL;
>  
>  	if (!acpi_drv->ops.add)


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diff mbox

Patch

Index: linux-pm/drivers/acpi/acpi_pnp.c
===================================================================
--- linux-pm.orig/drivers/acpi/acpi_pnp.c
+++ linux-pm/drivers/acpi/acpi_pnp.c
@@ -396,3 +396,8 @@  void __init acpi_pnp_init(void)
 {
 	acpi_scan_add_handler(&acpi_pnp_handler);
 }
+
+bool is_acpi_pnp_device(struct acpi_device *adev)
+{
+	return adev->handler == &acpi_pnp_handler;
+}
Index: linux-pm/drivers/acpi/internal.h
===================================================================
--- linux-pm.orig/drivers/acpi/internal.h
+++ linux-pm/drivers/acpi/internal.h
@@ -86,6 +86,7 @@  void acpi_device_add_finalize(struct acp
 void acpi_free_pnp_ids(struct acpi_device_pnp *pnp);
 bool acpi_device_is_present(struct acpi_device *adev);
 bool acpi_device_is_battery(struct acpi_device *adev);
+bool is_acpi_pnp_device(struct acpi_device *adev);
 
 /* --------------------------------------------------------------------------
                                   Power Resource
Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -975,7 +975,7 @@  static int acpi_device_probe(struct devi
 	struct acpi_driver *acpi_drv = to_acpi_driver(dev->driver);
 	int ret;
 
-	if (acpi_dev->handler)
+	if (acpi_dev->handler && !is_acpi_pnp_device(acpi_dev))
 		return -EINVAL;
 
 	if (!acpi_drv->ops.add)