[PATCH] power: Add legacy pm ops usage warning

[PATCH] power: Add legacy pm ops usage warning

[Shuah Khan]

Add legacy pm_ops usage checks to device_pm_add() when a device gets added
to PM core's list of active devices. If legacy pm_ops usage is found at its
class, bus, driver level, print warning message to indicate the driver code
needs updating to use dev pm ops interfaces. This will help serve as a way
to track drivers that still use legacy pm ops and fix them.

Signed-off-by: Shuah Khan <shuah.kh@samsung.com>
---
 drivers/base/power/main.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 9f098a8..4dc26dc 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -112,6 +112,23 @@ void device_pm_unlock(void)
 }
 
 /**
+ * check for lgeacy pm_ops usage and warn
+ */
+static void device_legacy_pm_ops_check(struct device *dev)
+{
+	char *info = "Please update driver to use dev pm_ops";
+
+	if (dev->class && (dev->class->suspend || dev->class->resume))
+		dev_warn(dev, "Driver uses legacy class pm ops - %s\n", info);
+
+	if (dev->bus && (dev->bus->suspend || dev->bus->resume))
+		dev_warn(dev, "Driver uses legacy bus pm ops - %s\n", info);
+
+	if (dev->driver && (dev->driver->suspend || dev->driver->resume))
+		dev_warn(dev, "Driver uses legacy pm ops - %s\n", info);
+}
+
+/**
  * device_pm_add - Add a device to the PM core's list of active devices.
  * @dev: Device to add to the list.
  */
@@ -123,6 +140,7 @@ void device_pm_add(struct device *dev)
 	if (dev->parent && dev->parent->power.is_prepared)
 		dev_warn(dev, "parent %s should not be sleeping\n",
 			dev_name(dev->parent));
+	device_legacy_pm_ops_check(dev);
 	list_add_tail(&dev->power.entry, &dpm_list);
 	mutex_unlock(&dpm_list_mtx);
 }
-- 
1.8.1.2

Re: [PATCH] power: Add legacy pm ops usage warning

[Rafael J. Wysocki]

On Friday, November 01, 2013 09:07:04 AM Shuah Khan wrote:
> Add legacy pm_ops usage checks to device_pm_add() when a device gets added
> to PM core's list of active devices. If legacy pm_ops usage is found at its
> class, bus, driver level, print warning message to indicate the driver code
> needs updating to use dev pm ops interfaces. This will help serve as a way
> to track drivers that still use legacy pm ops and fix them.

I think it would be much better to do these checks during bus type, class or
driver registration, because if you register a bus type with legacy PM, for
example, the check in device_pm_add() will trigger for all devices with that
bus type.

Thanks!

> Signed-off-by: Shuah Khan <shuah.kh@samsung.com>
> ---
>  drivers/base/power/main.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index 9f098a8..4dc26dc 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -112,6 +112,23 @@ void device_pm_unlock(void)
>  }
>  
>  /**
> + * check for lgeacy pm_ops usage and warn
> + */
> +static void device_legacy_pm_ops_check(struct device *dev)
> +{
> +	char *info = "Please update driver to use dev pm_ops";
> +
> +	if (dev->class && (dev->class->suspend || dev->class->resume))
> +		dev_warn(dev, "Driver uses legacy class pm ops - %s\n", info);
> +
> +	if (dev->bus && (dev->bus->suspend || dev->bus->resume))
> +		dev_warn(dev, "Driver uses legacy bus pm ops - %s\n", info);
> +
> +	if (dev->driver && (dev->driver->suspend || dev->driver->resume))
> +		dev_warn(dev, "Driver uses legacy pm ops - %s\n", info);
> +}
> +
> +/**
>   * device_pm_add - Add a device to the PM core's list of active devices.
>   * @dev: Device to add to the list.
>   */
> @@ -123,6 +140,7 @@ void device_pm_add(struct device *dev)
>  	if (dev->parent && dev->parent->power.is_prepared)
>  		dev_warn(dev, "parent %s should not be sleeping\n",
>  			dev_name(dev->parent));
> +	device_legacy_pm_ops_check(dev);
>  	list_add_tail(&dev->power.entry, &dpm_list);
>  	mutex_unlock(&dpm_list_mtx);
>  }
> 
-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.

Re: [PATCH] power: Add legacy pm ops usage warning

[Shuah Khan]

On 11/01/2013 05:04 PM, Rafael J. Wysocki wrote:
> On Friday, November 01, 2013 09:07:04 AM Shuah Khan wrote:
>> Add legacy pm_ops usage checks to device_pm_add() when a device gets added
>> to PM core's list of active devices. If legacy pm_ops usage is found at its
>> class, bus, driver level, print warning message to indicate the driver code
>> needs updating to use dev pm ops interfaces. This will help serve as a way
>> to track drivers that still use legacy pm ops and fix them.
>
> I think it would be much better to do these checks during bus type, class or
> driver registration, because if you register a bus type with legacy PM, for
> example, the check in device_pm_add() will trigger for all devices with that
> bus type.
>
> Thanks!

Rafael,

Correct. device_pm_add() triggers for all devices that use the driver. 
On the other hand, the check is done only when the device gets added to 
the pm core. I do like that part.

I am testing with adding checks driver_register() to look for suspend at 
bus level. I am not seeing the same set of drivers I saw with the check 
in device_pm_add(), which is puzzling. I am working on testing still. 
Keep you posted.

-- Shuah

-- 
Shuah Khan
Senior Linux Kernel Developer - Open Source Group
Samsung Research America(Silicon Valley)
shuah.kh@samsung.com | (970) 672-0658