[Bug][Patch] /dev/input/jsX absent for Nintendo Switch Pro controller

[Tom Benham]

First and foremost, apologies if this report is not properly done or formatted or whatever regarding the kernel development process. Feel free to correct me if I did something wrong.

Distribution: ArchLinux

$ cat /proc/version
Linux version 6.16-arch2-1 (linux@archlinux) (gcc (GCC) 15.2.1 20250813, GNU ld (GNU Binutils) 2.45.0) #3 SMP PREEMPT_DYNAMIC Sat, 16 Aug 2025 16:19:12 +0000

Problem description:
When plugging a Nintendo Switch Pro controller, the /dev/input/js0 file does not get created.

Problem analysis:
I think I have pinpointed the bug in the hid-nintendo.c driver.

• joydev (who is responsible for creating /dev/input/js0) is not handling the device.
• However, joydev receives the handling request from input.c only for the IMU device (the accelerometer), which is blacklisted (totally normal) so we get the following message when activating debug messages in joydev:
• input input39: joydev: blacklisting 'Nintendo Co., Ltd. Pro Controller (IMU)'
• joydev is looking for absbit and keybit in order to match a device (defined in joydev_ids array)
• But for the regular device (not IMU), absbit and keybit are 0
• The reason is that in joycon_input_create, input_register_device is called BEFORE setting the bits (which happen in joycon_config_*)
• This change was introduced in commit 94f18bb19945915fcdfd1903841020ef1b6af44a
• Before that, input_register_device was called AFTER setting the bits
• So, possible regression ? I can't test with older kernels unfortunately

I attached the simple patch that works for me.

Would it also make sense to move the rumble config before the call to input_register_device ? It was moved after the IMU device creation in the same commit, although I am not sure if it NEEDS to be. Let me know what you think of that.

Unrelated to the bug but I noticed during my testing that when first plugging the controller, when the hid_nintendo module is not loaded, hid-generic handles it but then it gets disconnected right after and hid_nintendo takes over. I'm very new to kernel debugging so I don't know if this behavior is normal but I guess it is. What's funny is that because hid-generic doesn't have the same bug, the /dev/input/js0 device gets created and then immediately removed. You can see it if you ls continuously the /dev/input folder. This was very confusing at first !

diff --git a/drivers/hid/hid-nintendo.c b/drivers/hid/hid-nintendo.c
index fb4985988615..a21618b42c38 100644
--- a/drivers/hid/hid-nintendo.c
+++ b/drivers/hid/hid-nintendo.c
@@ -2138,10 +2138,6 @@ static int joycon_input_create(struct joycon_ctlr *ctlr)
 	ctlr->input->phys = hdev->phys;
 	input_set_drvdata(ctlr->input, ctlr);
 
-	ret = input_register_device(ctlr->input);
-	if (ret)
-		return ret;
-
 	if (joycon_type_is_right_joycon(ctlr)) {
 		joycon_config_right_stick(ctlr->input);
 		joycon_config_buttons(ctlr->input, right_joycon_button_mappings);
@@ -2172,6 +2168,10 @@ static int joycon_input_create(struct joycon_ctlr *ctlr)
 		joycon_config_buttons(ctlr->input, n64con_button_mappings);
 	}
 
+	ret = input_register_device(ctlr->input);
+	if (ret)
+		return ret;
+
 	if (joycon_has_imu(ctlr)) {
 		ret = joycon_imu_input_create(ctlr);
 		if (ret)