From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp4-g21.free.fr (smtp4-g21.free.fr [212.27.42.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 166EE15C15F; Sat, 16 Aug 2025 18:24:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=212.27.42.4 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755368657; cv=none; b=Ta+UYtpMr1RUQF5ky6pLbOcBYIL5PK40xHdOmcICrqkv+iYVR52Rw4F1+j9AuU+QCj/lgCn8OICwJiZIm9r1PJluW/6r1AyokGdkRHBU3H7R12bsxVShjWCagfyP9IIupRwpGPw2bZ2hK4LuFc9dDO3Bqyacf+bzoOv/EQvwos8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755368657; c=relaxed/simple; bh=6O5N523WCTyTWnot0VxJfp/vgZYIQmHEvO5kzCfgTIg=; h=Content-Type:Message-ID:Date:MIME-Version:From:Subject:To:Cc; b=YQbvrHu2b/rcqKKsm7vs5B+pk7pwNvBSQtDkiO0KM5JFutlcHn3MW8PjCsFv/r/6LXDFRfy2FSkBHbRyDB9fm2Y5whW9tl0dBU2VK6/X4fmZR/+ulZ9pzcBsE6Z+BOT7D6Y9h7kLlfTgpfRn0/Y3L5tuscOMlwUvDZFqPTpwOBs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=free.fr; spf=pass smtp.mailfrom=free.fr; dkim=pass (2048-bit key) header.d=free.fr header.i=@free.fr header.b=VjgkORfj; arc=none smtp.client-ip=212.27.42.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=free.fr Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=free.fr Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=free.fr header.i=@free.fr header.b="VjgkORfj" Received: from [IPV6:2001:861:57c6:79d0:a4eb:e0da:cdee:91bc] (unknown [IPv6:2001:861:57c6:79d0:a4eb:e0da:cdee:91bc]) (Authenticated sender: tomben13@free.fr) by smtp4-g21.free.fr (Postfix) with ESMTPSA id CFA9419F576; Sat, 16 Aug 2025 20:24:10 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=free.fr; s=smtp-20201208; t=1755368651; bh=6O5N523WCTyTWnot0VxJfp/vgZYIQmHEvO5kzCfgTIg=; h=Date:From:Subject:To:Cc:From; b=VjgkORfjyUOqlEoIaGFF4Dc5CnrUpziHHX1UKQXi+vWHiQoFp2JqkjkprastBgygm Rkvkyfql5Mlobth7Q5uVoVrp23Tz+i8AgRLZpfOvF++1NmEX14lCDls1H+wuubzpeZ U1JBLnzEbY20ULAQigzKmWbHB0G9ad/ECPjjM/4ckocVThczfWdfwZ5cU8QsaPZ8xg XellSPqX0UPtVAJkhTG95zWczY/kvRSPB1ft2To6tNny47IhaWXkaDVB2vn1faEuaj NG44sCF8/bZ6i8rdKMqIvwiztRUpzCuuZXGUkMm/xqVpBSDxccIYYcxwSzo5/vXodi 6aE7wuCEYy8eQ== Content-Type: multipart/mixed; boundary="------------hRjbDyTg7mLmLz3i4cN3lQN3" Message-ID: Date: Sat, 16 Aug 2025 20:24:10 +0200 Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Tom Benham Subject: [Bug][Patch] /dev/input/jsX absent for Nintendo Switch Pro controller To: linux-input@vger.kernel.org Cc: linux-kernel@vger.kernel.org Content-Language: en-US This is a multi-part message in MIME format. --------------hRjbDyTg7mLmLz3i4cN3lQN3 Content-Type: multipart/alternative; boundary="------------LWzMZnYUId0q1ZdOaJUOuGtQ" --------------LWzMZnYUId0q1ZdOaJUOuGtQ Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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: o |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 ! --------------LWzMZnYUId0q1ZdOaJUOuGtQ Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit

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 !

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