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From: Sascha Hauer <s.hauer@pengutronix.de>
To: giorgio.nicole@arcor.de
Cc: barebox@lists.infradead.org
Subject: Re: problem configuring backlight brightness levels in device tree
Date: Wed, 13 Jul 2016 07:18:05 +0200	[thread overview]
Message-ID: <20160713051805.GZ20657@pengutronix.de> (raw)
In-Reply-To: <1745635830.58889.1468237871081.JavaMail.ngmail@webmail22.arcor-online.net>

On Mon, Jul 11, 2016 at 01:51:11PM +0200, giorgio.nicole@arcor.de wrote:
> Hi,
> 
> I was trying to configure a pwm backlight on an embedded arm board
> and I think I've found a minor problem.
> 
> In the source file 'drivers/video/backlight-pwm.c', in the function pwm_backlight_parse_dt()
> you set the number of brightness values to:
> 
> pwm_backlight->backlight.brightness_max = length / sizeof(u32);
> 
> and then loop through the array with:
> 
> for (i = 0; i <=  pwm_backlight->backlight.brightness_max; i++)
> 
> to find the max of the array.
> 
> I think the '<=' should be a '<' otherwise you access an uninitialized value
> one past the end of the array; this actually does not directly crash barebox
> but the whole brightness values are scaled wrong.

Yes, you're right. Can you send a patch for this?

Sascha

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  reply	other threads:[~2016-07-13  5:18 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-11 11:51 giorgio.nicole
2016-07-13  5:18 ` Sascha Hauer [this message]
2016-07-14 14:17   ` [PATCH 0/4] fixes some problems found in the backligth-pwm implementation iw3gtf
2016-07-14 14:17     ` [PATCH 1/4] video/backlight-pwm: fixed a loop index going out of range iw3gtf
2016-07-14 14:17     ` [PATCH 2/4] video/backlight-pwm: fix the value of 'brightness_max' iw3gtf
2016-07-14 14:17     ` [PATCH 3/4] video/backlight-pwm: code readability improvement iw3gtf
2016-07-14 14:17     ` [PATCH 4/4] video/backlight-pwm: properly handle the case of an empty 'brightness-levels' in the device tree iw3gtf
2016-07-15  6:07     ` [PATCH 0/4] fixes some problems found in the backligth-pwm implementation Sascha Hauer
2016-07-25  8:37     ` Sascha Hauer
2016-07-11 12:24 problem configuring backlight brightness levels in device tree iw3gtf

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