From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f49.google.com (mail-pj1-f49.google.com [209.85.216.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 96C513A6B73 for ; Tue, 21 Jul 2026 11:19:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.49 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784632777; cv=none; b=tFKJRez7xNZWvmvoi+adMUJnmOBemJpAproYvGDGftRV70v0mVQ3LeyNQiBhpdraiu7g9tVU6XhA3n9EocaVazY78ALbkQOztSp2yttLEpVoM7DSbWZA3DmnN5PctVFFtTpqlQSZput6c5Q2FTywLPqGt/MYhAgUKz1Qbya6N5w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784632777; c=relaxed/simple; bh=s7Sv44dJsqAFpIPuZKy6IKwqnLbr+yfy5ipG5K17i5c=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=kXgEpfnAC6QVFm2b2lntCuJ84dThVHfONGaUiY7aHBu/92dEN90rWeiP0D+uo38cZA1oeADuTi8YFPn/xH9xtJ6ST99UmNu9faHlQAjkWSw+4aJcpvfmr6Niv7VzgO5NopIrwg+u0t1dC3/MlS6frxr32CUHPtTAc6813Yyxxfs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=bsarD2ki; arc=none smtp.client-ip=209.85.216.49 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="bsarD2ki" Received: by mail-pj1-f49.google.com with SMTP id 98e67ed59e1d1-38e69bdb0fcso1928000a91.1 for ; Tue, 21 Jul 2026 04:19:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1784632773; x=1785237573; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=A1sboYn+PLqx0GjgQRMyl0bLfsK7YBG4P1Cv4h1Q/PY=; b=bsarD2kiV+X8gLP/LrQGzyI8MxbL6NknViCOMXSxcSYOYhHxG27yvpQ2BzyymAdMdY S9M+N5Ow4jf8I5PF7rSNbgpkVe2/7Myq4ZAjkeG3+kBccg10GFhGv3WMJyYym/EIyWSf s7WjbhvgyuKscn0MQ3DgcoYUF2afFMHi30fVBLcv15BLfwX9scfIHUD7l7tiMRd5mQqW 5LvaetHL4v5yPqrpQ6VB9XP1lt2dPWknQlJi+o9yzrS9LA+/VjKzoPzQ2CtsfGF/78Lc o9gSbli9romWwsp6nDPLvl+xrBdBaFiLpIO8ugq/SQnHs6GZc6WXKjCYME4smC/MbK+B hREA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784632773; x=1785237573; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=A1sboYn+PLqx0GjgQRMyl0bLfsK7YBG4P1Cv4h1Q/PY=; b=UJ06MKpYUu4N9LABDpeso/vi4zcmAcz8KpJAlIHh+/rC3il1c1Aypgesx+MuNkfIs5 8z3v98wkGVJxtUa0sDJYVa5x4DVtkPIj1WlH5N5h3oLEayILFBcxpE3xlocN+WS5sFS5 N/f62XkGVA/u+evQ5F+ae1OlXRFS/KRguiLf984O+qIo4PTvtccpmx9fDLZMYljKBu7G PrOI0SaDXT7I8km0mbLqNHd34WXnf4Eq/HPdgwDfACNL9LXOWrCj+MJiQSQJj3HYEzAx xpQb1u2A9lXcraO/F+HPKW7jQ4ULNzd8p42vqqStiDWN+awAjupWGfczo9sgnsqZKE7L hMmA== X-Forwarded-Encrypted: i=1; AHgh+RqwdPMc/JmtbuJ1gmidZLPx1h2Bf/maADurSSsoixRO/fEH79o57chkkrRJIE1rsQwB8NY0xJxr/StboC4=@vger.kernel.org X-Gm-Message-State: AOJu0Yw34C5bxmFRJC5KB1kpTk+ltbuPLBk2CjgAkpLJUgptEwb+2LCF CUedUFYkXLGqBMlqZvvcAqllBkJRRCH2exc430wVDa+eC8FwHGnLgLg= X-Gm-Gg: AR+sD11oqsXqRd+PbIqecwhbam8QkXWtVaNXBC4UK2pAJ4dP20Ik2/RH1ZutX2eqezY JiGwogap7Bwg5V5kJZHG+cgtsMg/agk1lwfvS5l25+O+fyzdCVI5EIExRdP3Sdhxli/ObsiTnmZ JmBz1rvdp9y8p6+e681/KbPjbcsutsLDyF7YH1kr4QpLtFatEh3bz5oUQQ06Z3XBzz1IH6IjhFQ MqN7lB9ZCYPV3J9BSHgdYHAJU3cJOygYZpyDFCTWym0OH19DOIfuXjXXWz1GfRhfg/ABWpazafr Ic21O7o9x6KsL4k+9OphAm3NlNL+lcCPa2KP5DUb4Rv8cUR/RBBViScp3ran0T7SU5+aY/SXklD 2MLTNxYyN3Dy/RrKJGLPeIFtPnmUPDCz/v5An0AHNtsyadg8OsWOON/ws62VAOza37rtpk823Oy eH5jfbcF4oj0GoonoRBPWMSmfGdh0aM5FWb3iLsLw= X-Received: by 2002:a17:90b:2890:b0:36d:7b62:4767 with SMTP id 98e67ed59e1d1-38e4b434f04mr18890851a91.5.1784632773222; Tue, 21 Jul 2026 04:19:33 -0700 (PDT) Received: from HPavillion15 ([2401:4900:8fe7:398d:8029:e3b8:bece:5845]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-13ce29ffb13sm40281251c88.6.2026.07.21.04.19.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Jul 2026 04:19:32 -0700 (PDT) From: Barath Kannan To: linux-input@vger.kernel.org Cc: Barath Kannan , linux-kernel@vger.kernel.org, dmitry.torokhov@gmail.com, bentiss@kernel.org, jikos@kernel.org Subject: [BUG] HID/input - Input misses when rapidly pressing consumer control keys on Logitech Media Keyboard K200 Date: Tue, 21 Jul 2026 16:49:15 +0530 Message-ID: <20260721111916.154338-1-barathrk11@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Description: When consumer control buttons such as volume up/down, pause/play etc of the Logitech Media Keyboard K200 are rapidly pressed, most of the inputs don't register properly. Environment used: - linux kernel 7.20.rc-4-dirty - qemu-system-x86_64 version 11.0.50. The arguments used were(This passes the keyboard through to qemu): -kernel "$BZIMAGE" -machine "q35" -cpu max -vga std -display gtk -device qemu-xhci,id=xhci -usb -device usb-host,bus=xhci.0,vendorid=0x046d,productid=0xc31d -initrd "$INITRAMFS_CPIO" -m 1G -smp 4 -no-reboot -virtfs "local,id=lkmpg,path=$PROJECT_ROOT,security_model=none,mount_tag=lkmpg" -append "nokaslr" (this is a slightly modified version of the qemu environment specified at the start of the Linux Kernel Module Programming Guide) - Qemu itself runs in a distrobox container running an Ubuntu 26.04 LTS - My host is Fedora Kinoite 43 with kernel version 6.17.12-300.fc43.x86_64(where I first noticed the issue) - The keyboard's vendorId : productId -> 046d:c31d Steps for reproduction: - Run hexdump -v on the appropriate /dev/input/event entry - Press the volume up button on the keyboard, slowly - Given enough time between key presses all presses cause a change in output with corresponding press/release entries - Rapidly press the volume up button on the keyboard - Notice that output either: 1. Doesn't change at all. 2. or after some time, it sort of gets flushed and you see a bunch of entries output all together. Expected Behaviour: Each button press/release should correspond to an event. Some Notes and Logs: - I concluded that this isn't likely to be a hardware issue as the expected behaviour was shown on Windows 11. - I noticed this issue first in kernel 6.12.12, and later I tested it in 7.20.rc-4-dirty and discovered that the issue still persists. - I hacked on the kernel in an attempt to figure out the problem myself, adding pr_info statements dumping state in evdev_read, input_event_dispose and hid_irq_in and saw the following(linked is my raw dmesg output without my changes, output grepping my pr_info statements and my .config. I have delimited the 3 sections by using a bunch of '=' characters): https://pastebin.com/59FsWsvq It seems to me that there are a lot of unnecessary SYN_REPORT calls with a disposition that triggers a flush of the device's inputs such as: [ 110.907511] input: input_event_dispose for device Logitech USB Keyboard Consumer Control of type: 0 code: 0 value: 0 dev->num_vals: 1 dev->max_vals: 11 [ 110.907543] input: input_event_dispose for device Logitech USB Keyboard System Control of type: 0 code: 0 value: 0 dev->num_vals: 1 dev->max_vals: 10 [ 111.035339] hid_irq_in device: 1133:49949 status: 0 [ 111.035412] input: input_event_dispose for device Logitech USB Keyboard Consumer Control of type: 0 code: 0 value: 0 dev->num_vals: 1 dev->max_vals: 11 [ 111.035431] input: input_event_dispose for device Logitech USB Keyboard System Control of type: 0 code: 0 value: 0 dev->num_vals: 1 dev->max_vals: 10 ...but I couldn't get any further than that. - Also, I noticed that the polling rate for consumer/system control is set to 255 ms whereas the main keyboard is set to 10 ms(I got this from the bInterval value while debugging). Would appreciate guidance on this.