Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755492AbcLZXBe (ORCPT ); Mon, 26 Dec 2016 18:01:34 -0500 Received: from 2.mo177.mail-out.ovh.net ([178.33.109.80]:39387 "EHLO 2.mo177.mail-out.ovh.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752131AbcLZXBc (ORCPT ); Mon, 26 Dec 2016 18:01:32 -0500 From: Lukasz Majewski To: Thierry Reding , Lee Jones , linux-pwm@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Liu Ying , Fabio Estevam , Fabio Estevam , Jingoo Han , Tomi Valkeinen , Lukasz Majewski Subject: [PATCH v2 RESEND] video: backlight: pwm_bl: Initialize fb_bl_on[x] and use_count during pwm_backlight_probe() Date: Mon, 26 Dec 2016 23:21:36 +0100 Message-Id: <1482790896-29202-1-git-send-email-l.majewski@majess.pl> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1477169904-14997-1-git-send-email-l.majewski@majess.pl> References: <1477169904-14997-1-git-send-email-l.majewski@majess.pl> X-Ovh-Tracer-Id: 10953035768746984069 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeelfedrledvgdduieduucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddm Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2051 Lines: 58 The commit a55944ca82d2 ("backlight: update bd state & fb_blank properties when necessary") has posed some extra restrictions on blanking and unblanking frame buffer device. Unfortunately, pwm_bl driver's probe did not initialize members of struct backlight_device necessary for further blank/unblank operation. This code in case of initial unblank of backlight device (default behaviour) sets use_count to 1 and marks this particular backlight device as used by all available fb devices (since it is not known during probe how much and which fb devices will be assigned). Without this code, the backlight works properly until one tries to blank it manually from sysfs with "echo 1 > /sys/class/graphics/fb0/blank". Since fb_bl_on[0] and use_count were both set to 0, the logic at fb_notifier_callback (@backlight.c) thought that we didn't turn on (unblanked) the backlight device and refuses to disable (blank) it. As a result we see garbage from fb displayed. Signed-off-by: Lukasz Majewski --- The patch has been tested on i.MX6q with vanilla 4.9 kernel. It applies on 4.10-rc1. --- drivers/video/backlight/pwm_bl.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 1261400..6859ba0 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -202,7 +202,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) struct pwm_bl_data *pb; int initial_blank = FB_BLANK_UNBLANK; struct pwm_args pargs; - int ret; + int ret, i; if (!data) { ret = pwm_backlight_parse_dt(&pdev->dev, &defdata); @@ -348,6 +348,14 @@ static int pwm_backlight_probe(struct platform_device *pdev) bl->props.brightness = data->dft_brightness; bl->props.power = initial_blank; + + if (initial_blank == FB_BLANK_UNBLANK) { + for (i = 0; i < FB_MAX; i++) + bl->fb_bl_on[i] = true; + + bl->use_count = 1; + } + backlight_update_status(bl); platform_set_drvdata(pdev, bl); -- 2.1.4