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From: giorgio.nicole@arcor.de
To: barebox@lists.infradead.org
Subject: problem configuring backlight brightness levels in device tree
Date: Mon, 11 Jul 2016 13:51:11 +0200 (CEST)	[thread overview]
Message-ID: <1745635830.58889.1468237871081.JavaMail.ngmail@webmail22.arcor-online.net> (raw)

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.

giorgio

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             reply	other threads:[~2016-07-11 12:26 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-11 11:51 giorgio.nicole [this message]
2016-07-13  5:18 ` Sascha Hauer
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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