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 9ED5138B7C4 for ; Wed, 3 Jun 2026 21:19:04 +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=1780521544; cv=none; b=pjR+MReGrRAAjLJugVfHVfdsTKyO8305yEI1sOtzF11U5m7qxk4LhLP7TDJhwSQo6xcMv9MpSeJ4joJbT5gLQFnYVlesVs+LJ5q4JnVzFtM0nZaMYJjJjfZabUVys5lHjTtVKdM9IYagUGbWCxdkS4OKnQECMgsykGDjubD7AbM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780521544; c=relaxed/simple; bh=iyXk8F5hJle3mKVFT1OJ4/fm2U8/kFvtdq1dVofCtM0=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=Q9njyJgZ26uk1OajhEuUDcyRiE2XKyj4NfQVSGBSkHQWuxdbjHUKnoGAf0Y3kdds1h+4H5RU+YsxXB/awpVOXDa5We6MLe4Ox+Qgkg37WX585TQ00TBnNXz3ER+9zDgvGhEKL8zYrHxvyffN/Ia1Q8qwTT97uyV9C5L9phG19rc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YoU7br1h; 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="YoU7br1h" Received: by smtp.kernel.org (Postfix) with ESMTPS id 2E570C2BCC4 for ; Wed, 3 Jun 2026 21:19:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1780521544; bh=iyXk8F5hJle3mKVFT1OJ4/fm2U8/kFvtdq1dVofCtM0=; h=From:To:Subject:Date:In-Reply-To:References:From; b=YoU7br1h1zTdf+TC7/owJFqbspgHuS83NktY+hY4bQ3tIHZtxLrQm4eTgVlWBDv4f 8bORueRAO8+LAMhCBKDbWm2U+v13OURpiEhLuZpVqAtE+spAAQAaEAqy9Yn6cAOcs1 lSoNNBv7HgxLghLEHy3rb7ZBoaHyYpNFqDh2++sw2jYLR+fRzMh824lHlmhDep052X dmeGXYNEwFB5UVZjff4UqscXVkpGjEMlp2f5dUM/6oXldDUWIeiF7u0VpzX57gKvjl JJ4AA8Fuo4COIIvbVaz2MmwZ54ZdojmUZjeDwf2sDYKL0QPQiiV+HGCdQFTnwZLJh9 0qSTfHRT17GDA== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id 125ECC3279F; Wed, 3 Jun 2026 21:19:04 +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 21:19:03 +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: george.stafilidis@proton.me 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 #6 from George (george.stafilidis@proton.me) --- Hi, following your advice, I dumped the EC MMIO region while cycling through the keyboard backlight states. I found a consistent pattern at offset 0x2A (Base address 0xFE00D400). Here are the exact values read from 0xFE00D42A for each state: Backlight OFF: 0x00000000FE00D42A: 00000001 (Hex: 0x01) Backlight LOW: 0x00000000FE00D42A: 00000011 (Hex: 0x03) Backlight HIGH: 0x00000000FE00D42A: 00000101 (Hex: 0x05) (Note: I identified the laptop in dmesg as ideapad_acpi VPC2004:00) Could this offset be used to implement software control via the ideapad-lap= top driver or a custom ACPI method? Let me know if you need any further dumps or testing! --=20 You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.=