From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zhang Rui Subject: Re: Question about ACPI Video Date: Tue, 26 Jan 2010 08:58:04 +0800 Message-ID: <1264467484.22448.310.camel@rzhang1-desktop> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mga01.intel.com ([192.55.52.88]:39327 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752632Ab0AZA73 (ORCPT ); Mon, 25 Jan 2010 19:59:29 -0500 In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: luke lin Cc: "linux-acpi@vger.kernel.org" , Luke lin On Mon, 2010-01-25 at 17:45 +0800, luke lin wrote: > Hi all, > > I read the drivers/acpi/video.c: > > 895 result = acpi_video_device_lcd_set_level(device, max_level); > 896 if (result) > 897 goto out_free_levels; > 898 > 899 result = acpi_video_device_lcd_get_level_current(device, &level); > 900 if (result) > 901 goto out_free_levels; > 902 > 903 br->flags._BQC_use_index = (level == max_level ? 0 : 1); > 904 > 905 if (!br->flags._BQC_use_index) { > 912 for (i = 2; i < br->count; i++) > 913 if (level_old == br->levels[i]) > 914 level = level_old; > 915 goto set_level; > 916 } > why after level == max_level, it will still need set_level again? > is this a bug, or it is necessary. > Because setting the backlight to max_level is just to check if _BQC uses indexed value. We need to set the backlight back after this is done. thanks, rui > thx > luke > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html