linux-kernel - Re: [PATCH v2] backlight: pwm_bl: Don't assign levels table repeatedly

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Message-ID: <20191003100206.ws35dbgifjwjicuv@holly.lan>
Date:   Thu, 3 Oct 2019 11:02:06 +0100
From:   Daniel Thompson <daniel.thompson@...aro.org>
To:     Matthias Kaehlcke <mka@...omium.org>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Lee Jones <lee.jones@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        linux-pwm@...r.kernel.org, linux-fbdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH v2] backlight: pwm_bl: Don't assign levels table
 repeatedly

On Wed, Oct 02, 2019 at 09:56:01AM -0700, Matthias Kaehlcke wrote:
> pwm_backlight_probe() re-assigns pb->levels for every brightness
> level. This is not needed and was likely not intended, since
> neither side of the assignment changes during the loop. Assign
> the field only once.
> 
> Signed-off-by: Matthias Kaehlcke <mka@...omium.org>

Reviewed-by: Daniel Thompson <daniel.thompson@...aro.org>

> ---
> 
> Changes in v2:
> - removed curly braces from for loop
> 
>  drivers/video/backlight/pwm_bl.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index 746eebc411df..05d3b3802658 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -564,18 +564,17 @@ static int pwm_backlight_probe(struct platform_device *pdev)
>  	memset(&props, 0, sizeof(struct backlight_properties));
>  
>  	if (data->levels) {
> +		pb->levels = data->levels;
> +
>  		/*
>  		 * For the DT case, only when brightness levels is defined
>  		 * data->levels is filled. For the non-DT case, data->levels
>  		 * can come from platform data, however is not usual.
>  		 */
> -		for (i = 0; i <= data->max_brightness; i++) {
> +		for (i = 0; i <= data->max_brightness; i++)
>  			if (data->levels[i] > pb->scale)
>  				pb->scale = data->levels[i];
>  
> -			pb->levels = data->levels;
> -		}
> -
>  		if (pwm_backlight_is_linear(data))
>  			props.scale = BACKLIGHT_SCALE_LINEAR;
>  		else
> -- 
> 2.23.0.444.g18eeb5a265-goog
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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