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 327342DEA74; Fri, 18 Jul 2025 17:13:32 +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=1752858813; cv=none; b=EkMAKu2sia3zubLKzf6s5c0bnIknvyQ5pbyg0zKD00u6GdEK+RG18A5jrROH4Ef7Z7TdaCiJZJzaU9qYq4TCiikfLNXgkCBxCN84eM0O210nmfGYckjLzqNORVxKsNve3yphnmot0h0SAzuj7aAVjm6DQej+zV+K81aRKxN1qRg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752858813; c=relaxed/simple; bh=2pMGWRUOR5c7ZDdNY06BPXHKdFbDc8dujXWYjj01bJw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=PIITH1apfe9QUI9lpbovxgANUgsYJ9x7ZY+EIUl9VZS+coWEaSzNQe+QBKPpY1/jhtPJaji+CZrWynUF6TIr/EvBg9dgV7hiWnAwb8MHsjAFXcKye4Bkrcw4I3RvcsjfWAJNMN12/iMxxd+PpDq/FwU2SVZmFDOPU5Jm10Tg0Mw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mQGamUG3; 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="mQGamUG3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 06757C4CEEB; Fri, 18 Jul 2025 17:13:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752858812; bh=2pMGWRUOR5c7ZDdNY06BPXHKdFbDc8dujXWYjj01bJw=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=mQGamUG3MbPPT3I1fdY9Esh2CwwC9tagkypvGkQlqv0/Vc/1oVyZyY0CqQGYCIggq fQS/4Hg4dFpwa7v6OTh0V2mhoq6AUM1Z8WuFOCey4/CC1pRu2Mtuw5MrUoVOh9e6rH D15hgvG2aPdwnAWfkJcG8VTRmtWmBErgGe4Fyvq6td77p5j5zaAVeoL4dhOzvtdH7t ML06TOWq18T5fWrwrXWFUdiCbagnZ/8uEKz0r1Wugg7Hcc+L3NDF4zPqRIL8LcbDaT 3+HwpqWSGUBz2wzuYphpJUA7YKXTzaQHsA3/WX2HdzU5Qx+2vloxgySMKR5kET9lZd lAw6rTVHS5T0Q== Message-ID: <46de4f2a-8836-42cd-a621-ae3e782bf253@kernel.org> Date: Fri, 18 Jul 2025 12:13:30 -0500 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [REGRESSION] drm/amd/display: backlight brightness set to 0 at amdgpu initialization To: Lauri Tirkkonen Cc: stable@vger.kernel.org, regressions@lists.linux.dev, amd-gfx@lists.freedesktop.org, Wayne Lin , Alex Deucher , Greg Kroah-Hartman References: Content-Language: en-US From: Mario Limonciello In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 7/18/2025 9:36 AM, Lauri Tirkkonen wrote: > On Fri, Jul 18 2025 08:10:06 -0500, Mario Limonciello wrote: >> Do you by chance have an OLED panel? I believe what's going on is that >> userspace is writing zero or near zero and on OLED panels with older kernels >> this means non-visible. > > Yes, this is an OLED panel. But I don't believe it's userspace writing > anything at this point in the boot; before the bisected commit, > brightness was set to 32 (out of max 255) on this hardware when I > checked from the initramfs rescue shell. At the bisected commit, it's 0 > (out of max 255). > >> There is another commit that fixes the behavior that is probably missing. > > Which commit is that? It's not in 6.15.7? > https://github.com/torvalds/linux/commit/39d81457ad3417a98ac826161f9ca0e642677661 No; it's not currently backported. Assuming it helps your issue I think it's a good argument to backport.