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 25DF338BF97 for ; Fri, 5 Jun 2026 05:55:30 +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=1780638931; cv=none; b=R2+DAPQaKbD8ewxVreX6S05dC2a+QbvOt0tuAge8I34WeH3SsypoWBTn6dhLXRzQiNG58F7S0bYD3B9/sQ+nnQZqPoxd2Gex2EQbzys/NuFZ7+UdJspQssMMgbhCK5K+uxflqd4MFu55lZA6NWv7qeuYM43Bv7CCGUolLtYLyMc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780638931; c=relaxed/simple; bh=kCDIziCWEey6W0djOQvMUs7Sh8YsVfGdgHkK4qXCd7A=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=OStADV7QTAjvMB6W2cY2gOGmP6uhYTFC3dw1eVUl7Uc14wqZdAMFGv0iLZvXT8VuNwc/pFy4y7XdsaZBZMA+GFDS+u0gXOjknN+r0lySGOok5Pip2N0XxeEt6cgSQ0647HMrK5KB9LZPzO7qEDUbud79M/TXXmbqk2bIEQDKtfo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ONrvzZs2; 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="ONrvzZs2" Received: by smtp.kernel.org (Postfix) with ESMTPS id BBFCBC2BCC7 for ; Fri, 5 Jun 2026 05:55:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1780638930; bh=kCDIziCWEey6W0djOQvMUs7Sh8YsVfGdgHkK4qXCd7A=; h=From:To:Subject:Date:In-Reply-To:References:From; b=ONrvzZs2qdZ8txFRSV2lEDbnbr64wWGIe6g6s/qD2FBNAnt4pTAASnJRrw6Az64ZU nzbMwpJkqobrHa/8F0gV71yxkLk/M+jXhfPB12CKDC52Ttp+6zvJK+2ikXmWtbr9E+ Uy7ldOZMMQUYoa0BgURhRhMNMCQIYbYT50bW0A2IjgV/U9I1sK743TcwPqytyUI5DN clM8EQV+UVI+kraTjwNyb6B6SWZEYxryDDNLhL8Wg7JOND+9FZ5JML8IOVx/6hIwdK SDrfjaoP7Bb9ZiTgrxS8oyRBScVmlGLfFByfTEPZgtZpWv5YQ6zIurEIji0SeN0wJd S6uQyfPxq4Q1Q== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id A0073C3279F; Fri, 5 Jun 2026 05:55:30 +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: Fri, 05 Jun 2026 05:55:30 +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: attachments.created 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 #12 from George (george.stafilidis@proton.me) --- Created attachment 310268 --> https://bugzilla.kernel.org/attachment.cgi?id=3D310268&action=3Dedit current dsdt.dsl Hi Rong, I=E2=80=99ve attached my current dsdt.dsl. With this version, the GNOME Qui= ck Settings panel correctly displays all three states (Off, Low, High), but clicking an= y of them has no effect on the physical backlight. Additionally, pressing Fn+Spa= ce no longer triggers the OSD popup at all. For context, I previously had a version where Off and Low worked physically= and the OSD appeared, but selecting High would instantly reset the state to Off. Through EC memory dumping, I confirmed my laptop uses register 0x8A (not 0x= 2A as in the original patch), and that writing 0x02 to the 2-bit KLEN field inadvertently sets the UCHE (USB Charging) bit, which cuts power to the backlight or whatever qwant thinks I have no idea. I=E2=80=99m not confident enough in ASL to resolve this safely. --=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.=