From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4/o+bxKjE1aXBQucx5TwxdVzNsoWG/XDwiANM8QdvjtPS4nFB2TnxjZPHRvcPE/sGWBxmKL ARC-Seal: i=1; a=rsa-sha256; t=1523399654; cv=none; d=google.com; s=arc-20160816; b=fUz1eenCnGii7l9IXhdfJjpgCDrpUHyRgFx+E4Vo/rJ3vGMraR/cHsh7mu2zVUfsBs bksCIWAMcp8IoDKyRfcvS9vajH4cREYymuwTek14TPXVcsbPBu1y/XWRKmPpnSDRxqSX bj5e06TCg6iBJ8FtbUd4mvKmigNsjm/pyGjqiGyuTRE3+tYZdaH0VEaaskc5AGRM4Om9 s+8KonsTEgr4eup+rTN6eUYheUDnREVZqWYeP9fYgTEf/r1471FozeOk52W5dYJp+HEK fr1VO7YaiNNtZL2cxQj7Rutg03oCCL7tPpbexVvVa9IRWqTj9aCpWodqNLCGig/OXT4z CAXw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=GJ99xkCiVUovRk/R3xg1qAgd4XqUrTSx2lSyArz3Zls=; b=rscawQhpxflmoYE4Nk4EGrkErK0Yn/DA1NTiP1E40ypo+8Aqx03SBZqs1blBcpqb/c B+7qUdmg8rNY3XFot4ZgKN4umxs4d813t6HD/2gwj2MlbpoYirC/FnESp5TDukHhS5tB rk3H86Fvbo0+/4fcxx8BCTC7nr1tVOk92D5wJjPW+A35DPP9HbxjcGUqy+hglz6MYjXh IrWT19oFEd0D1GO8svifg3rt7MpWkOls/m0gRu5cVI9SpbkvbUXjKwDLGoCFhJI+/sWm J7ozZCouo3Eucdj9bWMwPRu6Fw9vhMc3GVr2dOmrnSRJcDINlvh7g3pHLIGDsZUgMw8w q9iQ== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hans de Goede , "Rafael J. Wysocki" , Sasha Levin Subject: [PATCH 4.14 016/138] ACPI / video: Default lcd_only to true on Win8-ready and newer machines Date: Wed, 11 Apr 2018 00:23:26 +0200 Message-Id: <20180410212904.000064796@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180410212902.121524696@linuxfoundation.org> References: <20180410212902.121524696@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1597399882007140427?= X-GMAIL-MSGID: =?utf-8?q?1597400316455224232?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hans de Goede [ Upstream commit 5928c281524fe451114e04f1dfa11246a37e859f ] We're seeing a lot of bogus backlight interfaces on newer machines without a LCD such as desktops, servers and HDMI sticks. This causes userspace to show a non-functional brightness slider in e.g. the GNOME3 system menu, which is undesirable. And, in general, we should simply just not register a non functional backlight interface. Checking the LCD flag causes the bogus acpi_video backlight interfaces to go away (on the machines this was tested on). This change sets the lcd_only option by default on any machines which are Win8-ready, to fix this. This is not entirely without a risk of regressions, but video_detect.c already prefers native-backlight interfaces over the acpi_video one on Win8-ready machines, calling acpi_video_unregister_backlight() as soon as a native interface shows up. This is done because the ACPI backlight interface often is broken on Win8-ready machines, because win8 does not seem to actually use it. So in practice we already end up not registering the ACPI backlight interface on (most) Win8-ready machines with a LCD panel, thus this change does not change anything for (most) machines with a LCD panel and on machines without a LCD panel we actually don't want to register any backlight interfaces. This has been tested on the following machines and fixes a bogus backlight interface showing up there: - Desktop with an Asrock B150M Pro4S/D3 m.b. using i5-6500 builtin gfx - Intel Compute Stick STK1AW32SC - Meegopad T08 HDMI stick Bogus backlight interfaces have also been reported on: - Desktop with Asus H87I-Plus m.b. - Desktop with ASRock B75M-ITX m.b. - Desktop with Gigabyte Z87-D3HP m.b. - Dell PowerEdge T20 desktop Link: https://bugzilla.redhat.com/show_bug.cgi?id=1097436 Link: https://bugzilla.redhat.com/show_bug.cgi?id=1133327 Link: https://bugzilla.redhat.com/show_bug.cgi?id=1133329 Link: https://bugzilla.redhat.com/show_bug.cgi?id=1133646 Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/acpi/acpi_video.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) --- a/drivers/acpi/acpi_video.c +++ b/drivers/acpi/acpi_video.c @@ -80,8 +80,8 @@ MODULE_PARM_DESC(report_key_events, static bool device_id_scheme = false; module_param(device_id_scheme, bool, 0444); -static bool only_lcd = false; -module_param(only_lcd, bool, 0444); +static int only_lcd = -1; +module_param(only_lcd, int, 0444); static int register_count; static DEFINE_MUTEX(register_count_mutex); @@ -2136,6 +2136,16 @@ int acpi_video_register(void) goto leave; } + /* + * We're seeing a lot of bogus backlight interfaces on newer machines + * without a LCD such as desktops, servers and HDMI sticks. Checking + * the lcd flag fixes this, so enable this on any machines which are + * win8 ready (where we also prefer the native backlight driver, so + * normally the acpi_video code should not register there anyways). + */ + if (only_lcd == -1) + only_lcd = acpi_osi_is_win8(); + dmi_check_system(video_dmi_table); ret = acpi_bus_register_driver(&acpi_video_bus);