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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AD859C433F5 for ; Sun, 23 Jan 2022 09:11:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236040AbiAWJLG (ORCPT ); Sun, 23 Jan 2022 04:11:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230401AbiAWJLD (ORCPT ); Sun, 23 Jan 2022 04:11:03 -0500 Received: from mail-qv1-xf34.google.com (mail-qv1-xf34.google.com [IPv6:2607:f8b0:4864:20::f34]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9C8C9C06173B for ; Sun, 23 Jan 2022 01:11:03 -0800 (PST) Received: by mail-qv1-xf34.google.com with SMTP id k4so16652506qvt.6 for ; Sun, 23 Jan 2022 01:11:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=bl3efp74ab4pQlhH6DVOKc+JdDnTDiX+IOOPZRvKFIk=; b=ARUGGp+cvzIrVwH8Dm9kcolQ5ADQqS9hkzPW2oU/pvWuhoSxM/q+3AwrAeJ84YpQhJ 5ZhsIcShNnEkSJNMFsmOMMbtVITZdiRQP9QHx7G6IHtKcHdJEAggLTGWyQ+DgjxwpVZi +54QUmZ5MbQS+9QIAYpovzahcH2ewcRB9ki0m+sDijroUtEdAzackUaZmmiqZyeNDyGA E4fgcq0GyqKkeqm8d6Jrcq/h/HJmfxyg2VCSPbXDs+L+wOIDhP/JpI7difpGQHbau9HJ UQdz6DTVHWH8EAf0PVoPQO3hJfPhJyc0JRlbt9C9aTF8eu2gVyZbh6vXaNcsdOceFQa+ 47Gg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=bl3efp74ab4pQlhH6DVOKc+JdDnTDiX+IOOPZRvKFIk=; b=CFd0qWLzZUcu/APQgmBn+Nx5RTDKJIXLoJyvA2kJs6RM0S6EqoNP7AB0c8JVd0+90t iajnt4OwRRX9ryD9Ht+LKva+XmBRQfwk1vEuOYMuTpL0E1m0G6Qzt0k1Qya0FwRa83Rc Bj7EuNw+WVlu5ryWCtiVAqURxyCOBgAcJ74qf9SXiZVX4pCyNskFaSsQVS/7sfutVzCc rZUfMjQuvm9PaB7LfkpLEn+NoYaIpX5mAlNYOwU9EPLm0Gu82n+JVKc8xcHKBjAAxRhT cwwQYxKS1RkikRQV0PHLJrN7w1FR/j3NUQaSn9xbXJKkJ0fm8/PBslOLrGwv/pxFLahP RnaA== X-Gm-Message-State: AOAM532oLEnJIGGekHx2E0mz6mwiH6d06tXADjSSB5FSRuFfdrVnffd7 vo7BfMAKQ8AG22i5QuRPYbo= X-Google-Smtp-Source: ABdhPJzpO7Zzbcg01kfGn5FLWvm4y0zy0xN+rM7LtfVAM1UaB6ZlAdZ8qZNpdEmOBJYjasgcxGuM8A== X-Received: by 2002:a05:6214:260d:: with SMTP id gu13mr10100714qvb.100.1642929062764; Sun, 23 Jan 2022 01:11:02 -0800 (PST) Received: from tong-desktop.local (99-105-211-126.lightspeed.sntcca.sbcglobal.net. [99.105.211.126]) by smtp.googlemail.com with ESMTPSA id o126sm5479158qke.53.2022.01.23.01.11.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 23 Jan 2022 01:11:02 -0800 (PST) From: Tong Zhang To: Hans de Goede , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Cc: Tong Zhang Subject: [PATCH v2] drm/privacy-screen: honor acpi=off in detect_thinkpad_privacy_screen Date: Sun, 23 Jan 2022 01:10:04 -0800 Message-Id: <20220123091004.763775-1-ztong0001@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org when acpi=off is provided in bootarg, kernel crash with [ 1.252739] BUG: kernel NULL pointer dereference, address: 0000000000000018 [ 1.258308] Call Trace: [ 1.258490] ? acpi_walk_namespace+0x147/0x147 [ 1.258770] acpi_get_devices+0xe4/0x137 [ 1.258921] ? drm_core_init+0xc0/0xc0 [drm] [ 1.259108] detect_thinkpad_privacy_screen+0x5e/0xa8 [drm] [ 1.259337] drm_privacy_screen_lookup_init+0xe/0xe85 [drm] The reason is that acpi_walk_namespace expects acpi related stuff initialized but in fact it wouldn't when acpi is set to off. In this case we should honor acpi=off in detect_thinkpad_privacy_screen(). Signed-off-by: Tong Zhang --- v2: fix typo in previous commit -- my keyboard is eating letters drivers/gpu/drm/drm_privacy_screen_x86.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/drm_privacy_screen_x86.c b/drivers/gpu/drm/drm_privacy_screen_x86.c index a2cafb294ca6..e7aa74ad0b24 100644 --- a/drivers/gpu/drm/drm_privacy_screen_x86.c +++ b/drivers/gpu/drm/drm_privacy_screen_x86.c @@ -33,6 +33,9 @@ static bool __init detect_thinkpad_privacy_screen(void) unsigned long long output; acpi_status status; + if (acpi_disabled) + return false; + /* Get embedded-controller handle */ status = acpi_get_devices("PNP0C09", acpi_set_handle, NULL, &ec_handle); if (ACPI_FAILURE(status) || !ec_handle) -- 2.25.1