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 2313D29B77E for ; Fri, 5 Jun 2026 18:47:25 +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=1780685246; cv=none; b=qI8wwWVOW6gboOK01G/Ax32fDPElzWnirjnEwcgc1XqjaEMuXZXu02ThKLt3wFbxN2jH8O3cpDNR/hBTdvd1Jkeyd5JjbAgXW847sfiHynS/84qOejXrhlPTYyVtKpKyEcTRLTomV7hWrUjY022+Vf4AmzaHQarrajXoGdPpq8s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780685246; c=relaxed/simple; bh=kS08GOCm/0f+tUnU3oqjaghpO51ll/Prc/8egcDd3Iw=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=sVP+blpogsf8EZngliUHijhKR3EHZDsQxyiBboPs7GTDSQqAjwU4fKD8XzqDIApz3/OOPK12mjuCW2/D1Ptu0B5SCPU66v048BQvM+Jh92RgJAb6vYcgmTDX2oqWVs9/zEAZBTA+kArvC3jOemw9EwzJKM31CqQnUMtKBSIn45A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gNooafQE; 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="gNooafQE" Received: by smtp.kernel.org (Postfix) with ESMTPS id B44C8C2BCB4 for ; Fri, 5 Jun 2026 18:47:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1780685245; bh=kS08GOCm/0f+tUnU3oqjaghpO51ll/Prc/8egcDd3Iw=; h=From:To:Subject:Date:In-Reply-To:References:From; b=gNooafQEZrgI/tm7yUBasvyADB2VEN0XdUsEWyOb3AMzkFTN5PJCR4yQg8M8vdbSq yVu3YKlQ3pnRj/yksoUdXhJyFS7wZ9e1XA1AbH27bbhTj7N/hq/+8wsKDZQzHkRNz2 aGvCDUvFFoMVQX2NT66+iJPwx/KRTC1xs5Okrxt2erJPfXbAJD9Tf5b7cs6ZL8nrJ7 CNCrqN75F9/Y9yvMRVsH700oqu3HT/19fUxjhHo+aqPdkoIr8VMLLY1k5j4iQV3jai jB1DdJ4PMIall+/OGiJiQfjvMihhbNX74WKX9yJaYYwqR7/TK4fgBvmEenZ1zkpUb8 x7zdX2RNzW2ZQ== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id 975CDC3279F; Fri, 5 Jun 2026 18:47:25 +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 18:47:25 +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 #23 from Rong Zhang (i@rong.moe) --- (In reply to George from comment #22) > Thank you for the explanation and for your patience. I have attached > (dump_off.txt,dump_low.txt,dump_high.txt and dmesg_ec.txt) I hope i did it > correctly. Thanks. It did seem that 0x2A controlled the keyboard backlight brightness. > I did try the unmodified patch and from what i can see the GNOME Quick > Settings panel correctly displays all three states (Off, Low, High) but > dotes not change the brightness of they keyboard. Given that neither my patch nor manually writing to 0x2A worked, I guess th= e EC needs an additional synchronization mechanism to really trigger a brightness change from register writing. > Pressing Fn + Space > correctly triggers the OSD notification. i could upload a video if that's > possible to show you what I can see. (is it possible to upload mp4?) You don't need to upload a video. For now, I need the previous version of t= he DSDT code where "Off and Low worked physically and the OSD appeared" to fig= ure out what triggers the brightness change. --=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.=