From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 31D993A2544 for ; Wed, 3 Jun 2026 20:13:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780517598; cv=none; b=dfuJYheq2f+8slcWZPQ2D/Ak/Nqu/3QlAK6FrcJe5Ga6HChAYui8xLGO+h0kxD1TG+55EFzxhk+wIDDi75pEKVVoiTEtCqeBHwzq9tVDGbVRefcIbZSFUyDD8jegrcwJ2Wbgt6A1O0lDEaAF9Fq+LiKdx5ruePjG8sUhP6NBtnw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780517598; c=relaxed/simple; bh=d/qoz2gBerpMigakzWAv6iFaS06P8tzpUeGth8BRHbw=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=oPxcRKo5tStWvWt42mCPPBY7Z6LfBUAgg3VNApOp4LVDga0G7Jr/5f5lktozYZk+hRL8N/g4a0i+feTbMvshTv1f6ZFob3G40qqhVVz75WHm/OuMLfKNswIDI8OPK326f90N2cN3NcKcxCA46TC01R+9D84/kzBUG280RN3Kg4s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Z609fEOT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Z609fEOT" Received: by smtp.kernel.org (Postfix) with ESMTPS id ED246C2BCC6 for ; Wed, 3 Jun 2026 20:13:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1780517598; bh=d/qoz2gBerpMigakzWAv6iFaS06P8tzpUeGth8BRHbw=; h=From:To:Subject:Date:In-Reply-To:References:From; b=Z609fEOT4bxPTV/2ls0v512w2+GZTkB8b1VA4+dygU/09MeMjJhIB9mhtVZMbuZ61 vu/xh0UDwVZ1gJKjX6aMvG2NmHvVU/CH+HDrtYlyF7z6GZ9mHUtqE/gWpEvzhqa/v+ Nxg/sXeV0qAbavd50pDTENk3sBR4tuwEYKzCtiVUgsVxOJTacy+ifxGaPsvAt4oglR PoM6eL0DtwmslStT5pToLUSnfq5aZIDyRWHKt5nUok7tCnr7OlvLd9rnbjaEt/ZSjk pl3puBnhkZgg/VrxiiC1qZtdv4iViu/Ur2B52YTFVTpfLcchyv65ZZIyPVt8VqFZaB wi7alp+azna1Q== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id CB5ADC3279F; Wed, 3 Jun 2026 20:13:17 +0000 (UTC) From: bugzilla-daemon@kernel.org To: platform-driver-x86@vger.kernel.org Subject: [Bug 221583] Lenovo 82KU: keyboard backlight works via Fn+Space but no kbd_backlight LED device exposed Date: Wed, 03 Jun 2026 20:13:17 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo drivers_platform_x86@kernel-bugs.osdl.org X-Bugzilla-Product: Drivers X-Bugzilla-Component: Platform_x86 X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: i@rong.moe X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: drivers_platform_x86@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated Precedence: bulk X-Mailing-List: platform-driver-x86@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 https://bugzilla.kernel.org/show_bug.cgi?id=3D221583 --- Comment #5 from Rong Zhang (i@rong.moe) --- Hi George, Based on the debugfs dump and acpidump you provided, ideapad-laptop may not= be able to adjust keyboard backlight brightness as it does for other devices d= ue to the lack of relevant support in the ACPI table. That being said, if you would like to debug more, enable dynamic debug for = EC with... echo file drivers/acpi/ec.c +p | sudo tee /proc/dynamic_debug/control ...and cycle through all keyboard backlight brightness levels. Then dump dm= esg to see if any EC queries were executed. I also have a script (attached at the end) to dump the EC's MMIO region. Dumping it with different keyboard brightness levels and comparing the dumps may show some additional information: sudo bash /path/to/script.sh 0xFE00D400 0xFF 1 Note that dumping MMIO regions could be dangerous, so please save your open files and sync them to the disk before running the script. ```bash #!/bin/bash err() { echo "$*" >&2 exit 1 } declare -i base=3D$1 declare -i len=3D$2 ((base >=3D 0 && len > 0)) || err "Nothing to dump" declare -l acc=3D$3 declare -A supp=3D( [1]=3D1 [2]=3D2 [4]=3D4 [8]=3D8 [byte]=3D1 [word]=3D2 [dword]=3D4 [qword]=3D8 ) align=3D${supp[$acc]} [[ -n "$align" ]] || err "Unsupported access type: $acc" (( len < align )) && err "Length is too short: $len" bits=3D$((align * 8)) mask=3D$((align - 1)) (( base & mask )) && err "Misaligned base: $base" declare -A hex2bin=3D( [0]=3D0000 [1]=3D0001 [2]=3D0010 [3]=3D0011 [4]=3D0100 [5]=3D0101 [6]=3D0110 [7]=3D0111 [8]=3D1000 [9]=3D1001 [A]=3D1010 [B]=3D1011 [C]=3D1100 [D]=3D1101 [E]=3D1110 [F]=3D1111 ) for ((off =3D base; off <=3D base + len - align; off +=3D align)); do printf '0x%016X:' "$off" if ! out=3D$(busybox devmem "$off" "$bits" 2>&1); then echo " $out" continue fi printf -v hex "%0$((align * 2))X" "$((out))" for ((i =3D ${#hex} - 2; i >=3D 0; i -=3D 2)); do high=3D${hex:i:1} low=3D${hex:i+1:1} echo -n " ${hex2bin[$high]}${hex2bin[$low]}" done echo done ``` --=20 You may reply to this email to add a comment. 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