leds: core: avoid error message when a USB LED device is unplugged

PATCH Applied Heiner Kallweit 2 participants 2 messages Jan 22, 2016 LED

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Heiner Kallweit

author

2016-01-22 20:45 UTC #0 lore raw

PATCH v2 1/1 leds: core: avoid error message when a USB LED device is unplugged

When a USB LED device is unplugged the remove call chain calls led_classdev_unregister which tries to switch the LED off. As the device has been removed already this results in a ENODEV error message in dmesg.
Avoid this error message by ignoring ENODEV in calls from led_classdev_unregister if the LED device is flagged as pluggable.

Therefore a new flag LED_HW_PLUGGABLE was introduced which should be set by all LED drivers handling pluggable LED devices (mainly USB LED devices).

Signed-off-by Heiner Kallweit <[email protected]>

---
v2:
- rebased

---
 drivers/leds/led-class.c | 2 ++
 drivers/leds/led-core.c  | 5 ++++-
 include/linux/leds.h     | 2 ++
 3 files changed, 8 insertions(+), 1 deletion(-)

drivers/leds/led-class.c +2 -0

index 14139c3..aa84e5b 100644
@@ -245,6 +245,8 @@ void led_classdev_unregister(struct led_classdev *led_cdev)
 	up_write(&led_cdev->trigger_lock);
 #endif
 
+	led_cdev->flags |= LED_UNREGISTERING;
+
 	/* Stop blinking */
 	led_stop_software_blink(led_cdev);

drivers/leds/led-core.c +4 -1

index 19e1e60..ad684b6 100644
@@ -98,7 +98,10 @@ static void set_brightness_delayed(struct work_struct *ws)
 						led_cdev->delayed_set_value);
 	else
 		ret = -ENOTSUPP;
-	if (ret < 0)
+	if (ret < 0 &&
+	    /* LED HW might have been unplugged, therefore don't warn */
+	    !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) &&
+	    (led_cdev->flags & LED_HW_PLUGGABLE)))
 		dev_err(led_cdev->dev,
 			"Setting an LED's brightness failed (%d)\n", ret);
 }

include/linux/leds.h +2 -0

index e3470e7..f203a8f 100644
@@ -39,6 +39,7 @@ struct led_classdev {
 
 	/* Lower 16 bits reflect status */
 #define LED_SUSPENDED		(1 << 0)
+#define LED_UNREGISTERING	(1 << 1)
 	/* Upper 16 bits reflect control information */
 #define LED_CORE_SUSPENDRESUME	(1 << 16)
 #define LED_BLINK_ONESHOT	(1 << 17)

@@ -48,6 +49,7 @@ struct led_classdev {
 #define LED_BLINK_DISABLE	(1 << 21)
 #define LED_SYSFS_DISABLE	(1 << 22)
 #define LED_DEV_CAP_FLASH	(1 << 23)
+#define LED_HW_PLUGGABLE	(1 << 24)
 
 	/* Set LED brightness level
 	 * Must not sleep. Use brightness_set_blocking for drivers

Signature · 1 line

2.7.0

Jacek Anaszewski

Applied

2016-01-22 21:56 UTC #1 lore raw

Quoted 63 lines · Heiner Kallweit

Therefore a new flag LED_HW_PLUGGABLE was introduced which should be set by all LED drivers handling pluggable LED devices (mainly USB LED devices).

Signed-off-by Heiner Kallweit <[email protected]>

---
v2:
- rebased

---
  drivers/leds/led-class.c | 2 ++
  drivers/leds/led-core.c  | 5 ++++-
  include/linux/leds.h     | 2 ++
  3 files changed, 8 insertions(+), 1 deletion(-)

drivers/leds/led-class.c +2 -0

index 14139c3..aa84e5b 100644
@@ -245,6 +245,8 @@ void led_classdev_unregister(struct led_classdev *led_cdev)
  	up_write(&led_cdev->trigger_lock);
  #endif
 
+	led_cdev->flags |= LED_UNREGISTERING;
+
  	/* Stop blinking */
  	led_stop_software_blink(led_cdev);

drivers/leds/led-core.c +4 -1

index 19e1e60..ad684b6 100644
@@ -98,7 +98,10 @@ static void set_brightness_delayed(struct work_struct *ws)
  						led_cdev->delayed_set_value);
  	else
  		ret = -ENOTSUPP;
-	if (ret < 0)
+	if (ret < 0 &&
+	    /* LED HW might have been unplugged, therefore don't warn */
+	    !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) &&
+	    (led_cdev->flags & LED_HW_PLUGGABLE)))
  		dev_err(led_cdev->dev,
  			"Setting an LED's brightness failed (%d)\n", ret);
  }

include/linux/leds.h +1 -0

index e3470e7..f203a8f 100644
@@ -39,6 +39,7 @@ struct led_classdev {
 
  	/* Lower 16 bits reflect status */
  #define LED_SUSPENDED		(1 << 0)
+#define LED_UNREGISTERING	(1 << 1)
  	/* Upper 16 bits reflect control information */
  #define LED_CORE_SUSPENDRESUME	(1 << 16)
  #define LED_BLINK_ONESHOT	(1 << 17)

include/linux/leds.h struct led_classdev { · line 55

Quoted 7 lines

include/linux/leds.h +1 -0

@@ -48,6 +49,7 @@ struct led_classdev {
  #define LED_BLINK_DISABLE	(1 << 21)
  #define LED_SYSFS_DISABLE	(1 << 22)
  #define LED_DEV_CAP_FLASH	(1 << 23)
+#define LED_HW_PLUGGABLE	(1 << 24)
 
  	/* Set LED brightness level
  	 * Must not sleep. Use brightness_set_blocking for drivers

Applied to devel branch, thanks.

Signature · 2 lines

Best Regards,
Jacek Anaszewski