From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roland Stigge Subject: Re: [PATCH] samsung-laptop: Set keyboard backlight initially Date: Mon, 24 Dec 2012 13:55:30 +0100 Message-ID: <50D850C2.7050809@antcom.de> References: <1356283278-5046-1-git-send-email-stigge@antcom.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from antcom.de ([188.40.178.216]:59675 "EHLO chuck.antcom.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752321Ab2LXM5O (ORCPT ); Mon, 24 Dec 2012 07:57:14 -0500 In-Reply-To: Sender: platform-driver-x86-owner@vger.kernel.org List-ID: To: Corentin Chary Cc: gregkh@linuxfoundation.org, Matthew Garrett , "platform-driver-x86@vger.kernel.org" , LKML On 24/12/12 09:41, Corentin Chary wrote: > On Sun, Dec 23, 2012 at 6:21 PM, Roland Stigge wrote: >> After boot, /sys/devices/platform/samsung/leds/samsung::kbd_backlight/brightness >> shows the maximum value (8) by readout, but the led is off. I need to manually >> set it to the respective value to have keyboard backlight. > > If the led is set to 0, what's the value after reboot ? 0 or 8 ? Right - when writing 0 there before restart, the led value is actually 8 after reboot, and the LED hardware is ON. This holds for both reboot and halt+poweron cycle. Maybe this is related to the "#define MAX_BRIGHT 0x07" (which is unused in samsung-laptop.c)? A bit confusing in the code - but your question hints for some other bug (to be solved differently). Tell me if I can help somehow, here. > What's the behavior on windows ? There is no windows available on this machine. Thanks, Roland