linux-kernel - Re: [PATCH v2] pwm_bl: Fix overflow condition

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Message-ID: <20170830142741.GD1361@ulmo>
Date:   Wed, 30 Aug 2017 16:27:41 +0200
From:   Thierry Reding <thierry.reding@...il.com>
To:     Derek Basehore <dbasehore@...omium.org>
Cc:     linux-kernel@...r.kernel.org, jingoohan1@...il.com,
        lee.jones@...aro.org, briannorris@...omium.org,
        linux-pwm@...r.kernel.org
Subject: Re: [PATCH v2] pwm_bl: Fix overflow condition

On Tue, Aug 29, 2017 at 01:34:34PM -0700, Derek Basehore wrote:
> 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 <dbasehore@...omium.org>
> ---
>  drivers/video/backlight/pwm_bl.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)

I'm still confused by the brightness-levels-scale comment in the other
thread, but this looks like a good fix for a potential overflow so:

Acked-by: Thierry Reding <thierry.reding@...il.com>

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