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 67AFAC61DD6 for ; Sat, 29 Aug 2026 06:11:30 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 90B3510E092; Sat, 29 Aug 2026 06:11:29 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="GASuo+0b"; dkim-atps=neutral Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id EFB9E10E092 for ; Sat, 29 Aug 2026 06:11:27 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id AC79A43783 for ; Sat, 29 Aug 2026 06:11:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPS id 8E74FC2BCF7 for ; Sat, 29 Aug 2026 06:11:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1787983887; bh=CflGm107JU7yOMzaJ2kmhugdwlj1yCwaFjOm1qbNios=; h=From:To:Subject:Date:From; b=GASuo+0biLb4p80TE/awBIO0/Trxa5od3Hu5zEjr2lqtwLOQE1mwvxP4ltIAmjJaL y8TVccAZ3pirI4g9euaXU5Y+hN4diPwjGO68gFKx+HR8kJ1CRKJZ4mdMPT2zSt7xXy UwdVet7VeaS+FZLPKxs5enj0E7S9qV4r/G/rWn6X+XK4qAno45LG5ddO5gMzTTt/Gr uCavsiA69u4/+grm1cz/SXjlHObxSYEF5tpy7mRcRbghndt6Fa2QM6iIk4aLbGdgfk CtkWB2zn3tAJFWmSedhDWANZo7l3a717pHUQVjk1Mhxq5ZEwR6nhoJBLgrLlsM1zGa 5mkhpZptpxVGA== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id 6EFE5C41613; Sat, 29 Aug 2026 06:11:27 +0000 (UTC) From: bugzilla-daemon@kernel.org To: dri-devel@lists.freedesktop.org Subject: [Bug 221933] New: Screen brightness dimmer since kernel 7.2 (amdgpu) Date: Sat, 29 Aug 2026 06:11:27 +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: 3lefji@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=3D221933 Bug ID: 221933 Summary: Screen brightness dimmer since kernel 7.2 (amdgpu) Product: Drivers Version: 2.5 Hardware: All OS: Linux Status: NEW Severity: normal Priority: P3 Component: Video(DRI - non Intel) Assignee: drivers_video-dri@kernel-bugs.osdl.org Reporter: 3lefji@gmail.com Regression: No Hi everyone, Follow-up on a brightness issue I've been having since the kernel 7.2 update (still present in 7.2.2). Sharing what I found in case it helps others or points to the root cause. System info: - Laptop: Lenovo IdeaPad Gaming 3 - CPU: AMD Ryzen 5 5500H (iGPU handles the internal display backlight) - GPU: Nvidia RTX 2050 (hybrid AMD/Nvidia, PRIME render offload setup) - OS: Fedora 44, GNOME 50, Wayland - Kernel: 7.2.2-cachyos - Backlight device: amdgpu_bl1 Issue: since kernel 7.2, the same brightness percentage looks much dimmer t= han before. I used to sit around 30% in dim rooms, now I need about 60% for the same visual result. Raw values: ``` cat /sys/class/backlight/amdgpu_bl1/brightness -> 45755 cat /sys/class/backlight/amdgpu_bl1/max_brightness -> 65535 ``` So roughly 70% reported but visually much closer to what used to be ~30-35%. Looks like a mapping/curve change in the amdgpu backlight handling, similar= to reports I found for other kernel versions affecting amdgpu_bl on AMD laptops (both integrated and hybrid setups). I tried the common workaround of adding amdgpu.backlight=3Dvendor to GRUB_CMDLINE_LINUX. Brightness mapping did go back to normal after that cha= nge, BUT it caused severe system instability right after the password screen: extreme lag, barely able to move the mouse, a strange fade/scanline artifac= t on the lock screen, GPU idle at 32=C2=B0C while CPU sat at 13% doing nothing. = Had to revert the kernel parameter to get a usable system again. So amdgpu.backlight=3Dvendor is not a safe workaround at least on this hybr= id AMD/Nvidia + Wayland + GNOME 50 combination. Has anyone found a fix that doesn't cause this kind of freeze, or is this a case where we just need to wait for an upstream amdgpu fix? Happy to test patches or provide more logs if useful. Thanks! --=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.=