netdev - [PATCH] leds: trigger: netdev: skip setting baseline state in activate if hw-controlled

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Date: Wed, 29 Nov 2023 11:41:51 +0100
From: Heiner Kallweit <hkallweit1@...il.com>
To: Pavel Machek <pavel@....cz>, Lee Jones <lee@...nel.org>,
 Andrew Lunn <andrew@...n.ch>, Christian Marangi <ansuelsmth@...il.com>,
 Jakub Kicinski <kuba@...nel.org>
Cc: "linux-leds@...r.kernel.org" <linux-leds@...r.kernel.org>,
 "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH] leds: trigger: netdev: skip setting baseline state in
 activate if hw-controlled

The current codes uses the sw_control path in set_baseline_state() when
called from netdev_trig_activate() even if we're hw-controlled. This
may result in errors when led_set_brightness() is called because we may
not have set_brightness led ops (if hw doesn't support setting a LED
to ON).

Therefore set trigger_data->hw_control = true before calling
set_device_name() from netdev_trig_activate(). In this call chain we
have to prevent set_baseline_state() from being called, because this
would call hw_control_set(). Use led_cdev->trigger_data == NULL as
indicator for being called from netdev_trig_activate().

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
 drivers/leds/trigger/ledtrig-netdev.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/leds/trigger/ledtrig-netdev.c b/drivers/leds/trigger/ledtrig-netdev.c
index 7ed2d0b64..b58396600 100644
--- a/drivers/leds/trigger/ledtrig-netdev.c
+++ b/drivers/leds/trigger/ledtrig-netdev.c
@@ -251,7 +251,11 @@ static int set_device_name(struct led_netdev_data *trigger_data,
 
 	trigger_data->last_activity = 0;
 
-	set_baseline_state(trigger_data);
+	/* skip if we're called from netdev_trig_activate() and hw_control is true */
+	if (!trigger_data->hw_control ||
+	    led_get_trigger_data(trigger_data->led_cdev))
+		set_baseline_state(trigger_data);
+
 	mutex_unlock(&trigger_data->lock);
 	rtnl_unlock();
 
@@ -568,8 +572,8 @@ static int netdev_trig_activate(struct led_classdev *led_cdev)
 		if (dev) {
 			const char *name = dev_name(dev);
 
-			set_device_name(trigger_data, name, strlen(name));
 			trigger_data->hw_control = true;
+			set_device_name(trigger_data, name, strlen(name));
 
 			rc = led_cdev->hw_control_get(led_cdev, &mode);
 			if (!rc)
-- 
2.43.0