From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-op-o12.zoho.com (sender4-op-o12.zoho.com [136.143.188.12]) (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 1233D471CE4; Wed, 22 Jul 2026 16:40:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.12 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784738454; cv=pass; b=BUQ3XBevRVkAi1HdHgg++yEK9vyNPcY/IpyWyZazL29BTnwE1WrhUpsK99MYQhgB2N3+JgQWnp4ZmpNVH9Zp0YiiSChwdfh4e0Ia/wlPKTjfQj1lIdDZc0UWEIjo8wuUwqAfz3hrbGbsBcxoXJDkAW4yZye28C2Fv6Tx/QYKLqA= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784738454; c=relaxed/simple; bh=Hqd3Wa56l8zrCTwp+7xadt4cULrUkJxHXjy6wNs66S8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CgAxYJe+pG0Wx5nWfr5ocBpGbCEaoRWlOKd6Sti4dP1G+pX6zbReOzdL9FOteJw/gkz945dpprBHiS4PMeZW5BDRUVFzqO8IsNB2wtXpJDdOAwulEvo/Rtu6bhIQ0aaNg5JNI3j6C5vdPLtP7QATFvkyjkRbRF+YzV4So4N8UBE= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=ziyao.cc; spf=pass smtp.mailfrom=ziyao.cc; dkim=pass (1024-bit key) header.d=ziyao.cc header.i=me@ziyao.cc header.b=EnkHAL99; arc=pass smtp.client-ip=136.143.188.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=ziyao.cc Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ziyao.cc Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ziyao.cc header.i=me@ziyao.cc header.b="EnkHAL99" ARC-Seal: i=1; a=rsa-sha256; t=1784738413; cv=none; d=zohomail.com; s=zohoarc; b=VvrCmdmIeAP+oHE3sQxIA438g7kMdBAJxBc/5MSdQ278fwNQVWag2tA36Mm425SGY/u04Ig56vT4Q/uyOmgPp3r6nyRRUocm6kzTqPRAPEPccj003TZjdvL7BGkcSjZkl8qEpEaEzD4e/ko7SloG8SvprHNlSPsEqUsUdUCSDXs= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1784738413; h=Content-Type:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:Subject:Subject:To:To:Message-Id:Reply-To; bh=CFWy8us/akwOtk1Shi3kFXagj21q2YwusuaALSq7GP0=; b=DNQvvbCH91niP29JhYXBGcc9QnfTHcKl9JOH5jlUnKZWBQowZnhlGqqPof+B7DS0hE/gitAUSJSxPzHGMTSUgIBQeziKJBrj/u1TD8NoZIOoH1vDtDTXGLxf1AGux6T2euVGDijAEfb+/u8zVLd6uQaHr5kxp+IkYKoAlI6udqg= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=ziyao.cc; spf=pass smtp.mailfrom=me@ziyao.cc; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1784738413; s=zmail; d=ziyao.cc; i=me@ziyao.cc; h=Date:Date:From:From:To:To:Cc:Cc:Subject:Subject:Message-ID:MIME-Version:Content-Type:In-Reply-To:Message-Id:Reply-To; bh=CFWy8us/akwOtk1Shi3kFXagj21q2YwusuaALSq7GP0=; b=EnkHAL994i7MjiPYJwIs9mPD+iem5vMahUKoh5altZ5+J9so3XpHydS1E3XS+LtO IYDwHCJQImi2JhGLv60v3bhiNFzT+wZOqnfbUfjZvv2sQ/82d/2eepz8h11sfvIdRSv mRq4Q20R1QxpFm5UysqgA1QRv09ZHyls9OTsPy+c= Received: by mx.zohomail.com with SMTPS id 1784738410484852.0707588581733; Wed, 22 Jul 2026 09:40:10 -0700 (PDT) Date: Wed, 22 Jul 2026 16:39:59 +0000 From: Yao Zi To: liushuyu@aosc.io, linux-kernel@vger.kernel.org, Huacai Chen , Jianmin Lv , WANG Xuerui , Yao Zi Cc: loongarch@lists.linux.dev, Mingcong Bai , Kexy Biscuit , stable@vger.kernel.org, Yao Zi Subject: Re: [PATCH] platform/loongarch: laptop: explicitly reset the bl_powered state when resuming Message-ID: References: <20260722044457.1333404-1-liushuyu@aosc.io> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260722044457.1333404-1-liushuyu@aosc.io> X-Zoho-Virus-Status: 1 X-Zoho-AV-Stamp: zmail-av-0.2.10.1.5.2/284.732.17 X-ZohoMailClient: External On Wed, Jul 22, 2026 at 12:44:50PM +0800, liushuyu@aosc.io wrote: > From: Zixing Liu > > On EAECIS NL60R with EC firmware version 1.11, resuming from S3 has a very > high chance (>= 90%) of causing the EC to lose the previous backlight > power state. When this happens, the laptop resumes normally from S3, but > the backlight remains off (when shining on the screen with a flash light, > we can see the screen contents are updating normally). > > Since there is no generic way to query the EC's backlight state on > Loongson laptop platforms, assume the worst-case scenario and restart the > backlight power inside the kernel each time the system resumes. > > Cc: stable@vger.kernel.org > Fixes: 53c762b47f72 ("platform/loongarch: laptop: Add backlight power control support") > Signed-off-by: Zixing Liu Tested on my TongFang L860-T2 3A5000 laptop, which isn't affected by the EC issue, after resuming from S3 the brightness kept unchanged, no regression is observed. Tested-by: Yao Zi Regards, Yao Zi