From patchwork Fri Jan 24 06:04:36 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liu Ying X-Patchwork-Id: 3532991 Return-Path: X-Original-To: patchwork-linux-fbdev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 17420C02DC for ; Fri, 24 Jan 2014 06:04:40 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 421042015D for ; Fri, 24 Jan 2014 06:04:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 99EB820155 for ; Fri, 24 Jan 2014 06:04:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751686AbaAXGDm (ORCPT ); Fri, 24 Jan 2014 01:03:42 -0500 Received: from ch1ehsobe006.messaging.microsoft.com ([216.32.181.186]:11564 "EHLO ch1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751445AbaAXGDO (ORCPT ); Fri, 24 Jan 2014 01:03:14 -0500 Received: from mail28-ch1-R.bigfish.com (10.43.68.226) by CH1EHSOBE013.bigfish.com (10.43.70.63) with Microsoft SMTP Server id 14.1.225.22; Fri, 24 Jan 2014 06:03:13 +0000 Received: from mail28-ch1 (localhost [127.0.0.1]) by mail28-ch1-R.bigfish.com (Postfix) with ESMTP id C847820013C; Fri, 24 Jan 2014 06:03:13 +0000 (UTC) X-Forefront-Antispam-Report: CIP:70.37.183.190; KIP:(null); UIP:(null); IPV:NLI; H:mail.freescale.net; RD:none; EFVD:NLI X-SpamScore: 0 X-BigFish: VS0(zzzz1f42h2148h208ch1ee6h1de0h1fdah2073h2146h1202h1e76h2189h1d1ah1d2ah21bch1fc6hzz1de098h8275bh1de097hz2dh2a8h839he5bhf0ah1288h12a5h12a9h12bdh12e5h137ah139eh13b6h1441h1504h1537h162dh1631h1758h1898h18e1h1946h19b5h1ad9h1b0ah1b2fh2222h224fh1fb3h1d0ch1d2eh1d3fh1dfeh1dffh1e23h1fe8h1ff5h2218h2216h226dh22d0h24afh2327h2336h2438h2461h2487h24d7h1155h) Received: from mail28-ch1 (localhost.localdomain [127.0.0.1]) by mail28-ch1 (MessageSwitch) id 1390543391764784_12581; Fri, 24 Jan 2014 06:03:11 +0000 (UTC) Received: from CH1EHSMHS006.bigfish.com (snatpool1.int.messaging.microsoft.com [10.43.68.253]) by mail28-ch1.bigfish.com (Postfix) with ESMTP id AAF3F440064; Fri, 24 Jan 2014 06:03:11 +0000 (UTC) Received: from mail.freescale.net (70.37.183.190) by CH1EHSMHS006.bigfish.com (10.43.70.6) with Microsoft SMTP Server (TLS) id 14.16.227.3; Fri, 24 Jan 2014 06:03:11 +0000 Received: from tx30smr01.am.freescale.net (10.81.153.31) by 039-SN1MMR1-003.039d.mgd.msft.net (10.84.1.16) with Microsoft SMTP Server (TLS) id 14.3.158.2; Fri, 24 Jan 2014 06:03:10 +0000 Received: from victor.ap.freescale.net (victor.ap.freescale.net [10.192.241.62]) by tx30smr01.am.freescale.net (8.14.3/8.14.0) with ESMTP id s0O630gN029004; Thu, 23 Jan 2014 23:03:08 -0700 From: Liu Ying To: CC: , , , , , Subject: [PATCH v4 2/2] backlight: update backlight status when necessary Date: Fri, 24 Jan 2014 14:04:36 +0800 Message-ID: <1390543476-13499-3-git-send-email-Ying.Liu@freescale.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1390543476-13499-1-git-send-email-Ying.Liu@freescale.com> References: <1390543476-13499-1-git-send-email-Ying.Liu@freescale.com> MIME-Version: 1.0 X-OriginatorOrg: freescale.com X-FOPE-CONNECTOR: Id%0$Dn%*$RO%0$TLS%0$FQDN%$TlsDn% Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We don't have to update a backlight status every time a blanking or unblanking event comes because the backlight status may have already been what we want. Another thought is that one backlight device may be shared by multiple framebuffers. We don't hope blanking one of the framebuffers may turn the backlight off for all the other framebuffers, since they are likely being active to display something. This patch makes the backlight status be updated only when the relevant backlight device's use count changes from zero to one or from one to zero. Signed-off-by: Liu Ying --- drivers/video/backlight/backlight.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c index efc9a2d..27d3cf2 100644 --- a/drivers/video/backlight/backlight.c +++ b/drivers/video/backlight/backlight.c @@ -34,7 +34,7 @@ static const char *const backlight_types[] = { defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)) /* This callback gets called when something important happens inside a * framebuffer driver. We're looking if that important event is blanking, - * and if it is, we're switching backlight power as well ... + * and if it is and necessary, we're switching backlight power as well ... */ static int fb_notifier_callback(struct notifier_block *self, unsigned long event, void *data) @@ -60,6 +60,7 @@ static int fb_notifier_callback(struct notifier_block *self, if (!bd->use_count++) { bd->props.state &= ~BL_CORE_FBBLANK; bd->props.fb_blank = FB_BLANK_UNBLANK; + backlight_update_status(bd); } } else if (fb_blank != FB_BLANK_UNBLANK && bd->fb_bl_on[node]) { @@ -67,9 +68,9 @@ static int fb_notifier_callback(struct notifier_block *self, if (!(--bd->use_count)) { bd->props.state |= BL_CORE_FBBLANK; bd->props.fb_blank = fb_blank; + backlight_update_status(bd); } } - backlight_update_status(bd); } mutex_unlock(&bd->ops_lock); return 0;