[PATCH RFC 1/2] HID: hid-oxp: Replace system_wq with system_dfl_wq

[Marco Crivellari]

The function end up calling __queue_delayed_work(), which set a global
timer that could fire anywhere, enqueuing the work where the timer fired.

Unbound works could benefit from scheduler task placement, to optimize
performance and power consumption.

Since the workqueue work doesn't rely on per-cpu variables, there is no
obvious reason that justify the use of a per-cpu workqueue. So change the
workqueue with the new unbound version, system_dfl_wq.

Cc: Derek J. Clark <derekjohn.clark@xxxxxxxxx>
Signed-off-by: Marco Crivellari <marco.crivellari@xxxxxxxx>
---
 drivers/hid/hid-oxp.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-oxp.c b/drivers/hid/hid-oxp.c
index 20a54f337220..d2ded6b08ce9 100644
--- a/drivers/hid/hid-oxp.c
+++ b/drivers/hid/hid-oxp.c
@@ -398,7 +398,7 @@ static int oxp_hid_raw_event_gen_2(struct hid_device *hdev,
 	 * Re-apply our settings after this has been received.
 	 */
 	if (data[3] == OXP_EFFECT_MONO_TRUE) {
-		mod_delayed_work(system_wq, &drvdata.oxp_mcu_init, msecs_to_jiffies(50));
+		mod_delayed_work(system_dfl_wq, &drvdata.oxp_mcu_init, msecs_to_jiffies(50));
 		return 0;
 	}
 
@@ -788,7 +788,7 @@ static ssize_t map_button_store(struct device *dev,
 	default:
 		return -EINVAL;
 	}
-	mod_delayed_work(system_wq, &drvdata.oxp_btn_queue, msecs_to_jiffies(50));
+	mod_delayed_work(system_dfl_wq, &drvdata.oxp_btn_queue, msecs_to_jiffies(50));
 	return count;
 }
 
@@ -1349,7 +1349,7 @@ static void oxp_rgb_brightness_set(struct led_classdev *led_cdev,
 				   enum led_brightness brightness)
 {
 	led_cdev->brightness = brightness;
-	mod_delayed_work(system_wq, &drvdata.oxp_rgb_queue, msecs_to_jiffies(50));
+	mod_delayed_work(system_dfl_wq, &drvdata.oxp_rgb_queue, msecs_to_jiffies(50));
 }
 
 static struct attribute *oxp_rgb_attrs[] = {
@@ -1502,7 +1502,7 @@ static int oxp_cfg_probe(struct hid_device *hdev, u16 up)
 	drvdata.rumble_intensity = 5;
 
 	INIT_DELAYED_WORK(&drvdata.oxp_mcu_init, oxp_mcu_init_fn);
-	mod_delayed_work(system_wq, &drvdata.oxp_mcu_init, msecs_to_jiffies(50));
+	mod_delayed_work(system_dfl_wq, &drvdata.oxp_mcu_init, msecs_to_jiffies(50));
 
 	ret = devm_device_add_group(&hdev->dev, &oxp_cfg_attrs_group);
 	if (ret)
-- 
2.54.0