Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761092AbbKTXQe (ORCPT ); Fri, 20 Nov 2015 18:16:34 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:55713 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759785AbbKTXQd (ORCPT ); Fri, 20 Nov 2015 18:16:33 -0500 Date: Fri, 20 Nov 2015 15:16:32 -0800 From: Darren Hart To: Azael Avalos Cc: platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Fabian Koester Subject: Re: [PATCH] toshiba_acpi: Fix blank screen at boot if transflective backlight is supported Message-ID: <20151120231632.GC7413@malice.jf.intel.com> References: <1447644767-356-1-git-send-email-coproscefalo@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1447644767-356-1-git-send-email-coproscefalo@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2230 Lines: 56 On Sun, Nov 15, 2015 at 08:32:47PM -0700, Azael Avalos wrote: > 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. So... I'm not sure this is a bug or even wrong behavior. The lowest setting on my Thinkpad Yoga 12 is also "off" in Linux. Same is true for my Mac Book Pro (in Mac OS X). >From what I can tell, what this patch does is merely disable the lowest setting. What is it about this behavior that is considered to be wrong? > > Cc: # 4.3+ > Reported-and-tested-by: Fabian Koester > Signed-off-by: Azael Avalos > --- > drivers/platform/x86/toshiba_acpi.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/platform/x86/toshiba_acpi.c b/drivers/platform/x86/toshiba_acpi.c > index 2ca3f91..b6a7dc9 100644 > --- a/drivers/platform/x86/toshiba_acpi.c > +++ b/drivers/platform/x86/toshiba_acpi.c > @@ -2634,6 +2634,14 @@ static int toshiba_acpi_setup_backlight(struct toshiba_acpi_dev *dev) > 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"); > -- > 2.6.2 > > -- Darren Hart Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/