Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932384AbcCBAbj (ORCPT ); Tue, 1 Mar 2016 19:31:39 -0500 Received: from mail333.us4.mandrillapp.com ([205.201.137.77]:58676 "EHLO mail333.us4.mandrillapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756307AbcCAX5Z (ORCPT ); Tue, 1 Mar 2016 18:57:25 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; q=dns; s=mandrill; d=linuxfoundation.org; b=FjNjdQbPNxEea6pwSBsrRDWlLK0yyhzmmYjjrblVoXLcLdyLCC2fLnf9C3j2uXr7gdXt9F7WEWm1 STD43T+TAvV/f9B2lgi6DYZdxY8PADTlx/fbXcmomzAHB0FNSqvB4thc60fZ1QoWQA8XoFofp6q7 VoO6yOPWKZ7qYShhf2M=; From: Greg Kroah-Hartman Subject: [PATCH 4.4 236/342] toshiba_acpi: Fix blank screen at boot if transflective backlight is supported X-Mailer: git-send-email 2.7.2 To: Cc: Greg Kroah-Hartman , , Azael Avalos , Darren Hart Message-Id: <20160301234535.546822639@linuxfoundation.org> In-Reply-To: <20160301234527.990448862@linuxfoundation.org> References: <20160301234527.990448862@linuxfoundation.org> X-Report-Abuse: Please forward a copy of this message, including all headers, to abuse@mandrill.com X-Report-Abuse: You can also report abuse here: http://mandrillapp.com/contact/abuse?id=30481620.f18b5b26dfd64cb2bddea1fc6644d4a9 X-Mandrill-User: md_30481620 Date: Tue, 01 Mar 2016 23:55:02 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1602 Lines: 41 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Azael Avalos commit bae5336f0aaedffa115dab9cb3d8a4e4aed3a26a upstream. If transflective backlight is supported and the brightness is zero (lowest brightness level), the set_lcd_brightness function will activate the transflective backlight, making the LCD appear to be turned off. This patch fixes the issue by incrementing the brightness level, and by doing so, avoiding the activation of the tranflective backlight. Reported-and-tested-by: Fabian Koester Signed-off-by: Azael Avalos Signed-off-by: Darren Hart Signed-off-by: Greg Kroah-Hartman --- drivers/platform/x86/toshiba_acpi.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/drivers/platform/x86/toshiba_acpi.c +++ b/drivers/platform/x86/toshiba_acpi.c @@ -2484,6 +2484,14 @@ static int toshiba_acpi_setup_backlight( brightness = __get_lcd_brightness(dev); if (brightness < 0) return 0; + /* + * If transflective backlight is supported and the brightness is zero + * (lowest brightness level), the set_lcd_brightness function will + * activate the transflective backlight, making the LCD appear to be + * turned off, simply increment the brightness level to avoid that. + */ + if (dev->tr_backlight_supported && brightness == 0) + brightness++; ret = set_lcd_brightness(dev, brightness); if (ret) { pr_debug("Backlight method is read-only, disabling backlight support\n");