From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:38186 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755844AbdLTRUT (ORCPT ); Wed, 20 Dec 2017 12:20:19 -0500 Subject: Patch "backlight: pwm_bl: Fix overflow condition" has been added to the 4.14-stable tree To: dbasehore@chromium.org, alexander.levin@verizon.com, briannorris@chromium.org, gregkh@linuxfoundation.org, lee.jones@linaro.org, thierry.reding@gmail.com Cc: , From: Date: Wed, 20 Dec 2017 18:20:08 +0100 Message-ID: <151379040816533@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled backlight: pwm_bl: Fix overflow condition to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: backlight-pwm_bl-fix-overflow-condition.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Wed Dec 20 18:17:52 CET 2017 From: Derek Basehore Date: Tue, 29 Aug 2017 13:34:34 -0700 Subject: backlight: pwm_bl: Fix overflow condition From: Derek Basehore [ Upstream commit 5d0c49acebc9488e37db95f1d4a55644e545ffe7 ] This fixes an overflow condition that can happen with high max brightness and period values in compute_duty_cycle. This fixes it by using a 64 bit variable for computing the duty cycle. Signed-off-by: Derek Basehore Acked-by: Thierry Reding Reviewed-by: Brian Norris Signed-off-by: Lee Jones Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/video/backlight/pwm_bl.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -79,14 +79,17 @@ static void pwm_backlight_power_off(stru static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness) { unsigned int lth = pb->lth_brightness; - int duty_cycle; + u64 duty_cycle; if (pb->levels) duty_cycle = pb->levels[brightness]; else duty_cycle = brightness; - return (duty_cycle * (pb->period - lth) / pb->scale) + lth; + duty_cycle *= pb->period - lth; + do_div(duty_cycle, pb->scale); + + return duty_cycle + lth; } static int pwm_backlight_update_status(struct backlight_device *bl) Patches currently in stable-queue which might be from dbasehore@chromium.org are queue-4.14/backlight-pwm_bl-fix-overflow-condition.patch