From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2D8F8C5B56E for ; Fri, 20 Feb 2026 21:37:28 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4B39F10E318; Fri, 20 Feb 2026 21:37:27 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="Td+dVduN"; dkim-atps=neutral Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id 408B910E318 for ; Fri, 20 Feb 2026 21:37:26 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 63FD460134 for ; Fri, 20 Feb 2026 21:37:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPS id 174BEC116C6 for ; Fri, 20 Feb 2026 21:37:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771623445; bh=NJK8OdBozaXkLWqivw8B99Q0CfGooDa3a69KnlN5o4k=; h=From:To:Subject:Date:From; b=Td+dVduNKsn3/xRAM9Tl0O+ou87G2BpjYdwC6sfqTMNGnMG9/QpYx2H7/R+6aiBB4 8MiC09TKXNBpn3No5WVkT7s0nwNMplX/wk1NTpDZgQrD5vbtdQEDxJwhBf1t3JL7Od nq1tLv4Mx+WBTOusCNnvqcRG3jC1Yd7yWkKLEqYGlAGOdnw+PmdbKBhkXGmA/necHi nyCaLQ7UDV9WnV0Q2g+tVm4S5x+VgdSqExO7RlsnivsuRWje8IYx97JcngyxLgn/G3 i8OXdQyG7l7s7Oy7+vvOVPDh0fTzKWQQBZGP5QzA4poSScCrjqPgJENK/r62NmCBUZ PAxtP0G2EgzOA== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id 0F53AC41613; Fri, 20 Feb 2026 21:37:25 +0000 (UTC) From: bugzilla-daemon@kernel.org To: dri-devel@lists.freedesktop.org Subject: [Bug 221110] New: amdgpu DM skips backlight registration on ASUS TUF A14 (DCN 3.5) due to ATPX detection regardless of active GPU mode Date: Fri, 20 Feb 2026 21:37:24 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: AssignedTo drivers_video-dri@kernel-bugs.osdl.org X-Bugzilla-Product: Drivers X-Bugzilla-Component: Video(DRI - non Intel) X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: maurotibanez@gmail.com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: drivers_video-dri@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter cf_regression Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" https://bugzilla.kernel.org/show_bug.cgi?id=3D221110 Bug ID: 221110 Summary: amdgpu DM skips backlight registration on ASUS TUF A14 (DCN 3.5) due to ATPX detection regardless of active GPU mode Product: Drivers Version: 2.5 Hardware: AMD OS: Linux Status: NEW Severity: normal Priority: P3 Component: Video(DRI - non Intel) Assignee: drivers_video-dri@kernel-bugs.osdl.org Reporter: maurotibanez@gmail.com Regression: No Hardware: Laptop: ASUS TUF A14 Panel: BOE NE140QDM-NX7 iGPU: AMD (DCN 3.5) dGPU: NVIDIA (disabled via vga_switcheroo / supergfxctl, Integrated mode active) Kernel: 6.17.9-76061709-generic Problem: No backlight device is registered in /sys/class/backlight/ when booting in Integrated GPU mode. Brightness control is completely non-functional. Kernel log showing root cause: [3.831962] amdgpu: vga_switcheroo: detected switching method \_SB_.PCI0.GPPA.VGA_.ATPX handle [3.832035] amdgpu: ATPX version 1, functions 0x00000801 [3.832077] amdgpu: ATPX Hybrid Graphics [4.320982] amdgpu 0000:65:00.0: amdgpu: [drm] Skipping amdgpu DM backlight registration The amdgpu driver detects ATPX at 3.83s and skips backlight registration at 4.32s. The skip occurs unconditionally based on ATPX presence, without chec= king whether vga_switcheroo has actually handed display control to the iGPU. Whe= n in Integrated mode, amdgpu owns the display pipeline (DCN 3.5 active, eDP-1 connected to card0) but does not register a backlight device. Confirmed not caused by: asus_wmi / asus-nb-wmi (loads at 6.08s, after the skip at 4.32s) Missing ACPI backlight method (DSDT contains no backlight method) Panel quirk (BOE NE140QDM-NX7 has no known quirk entry) Kernel parameters tested with no effect: amdgpu.backlight=3D0 / amdgpu.backlight=3D1 acpi_backlight=3Dnative acpi_backlight=3Dvideo acpi_backlight=3Dvendor ATPX functions value: 0x00000801 Expected behavior: When vga_switcheroo/supergfxctl has placed the system in Integrated mode and the AMD iGPU owns the display pipeline, amdgpu DM should register a backlig= ht device normally regardless of ATPX presence. Additional info: /proc/acpi/video/ does not exist card0-eDP-1 is the active internal panel path NVIDIA modules are fully unloaded in Integrated mode supergfxctl -g confirms Integrated --=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.=