linux-kernel - Re: [PATCH 5/7] fbdev/core: Build fb_logo iff CONFIG

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Message-ID: <bf8e8402-2def-a365-18be-3b426cb1830a@gmx.de>
Date:   Fri, 1 Sep 2023 10:22:05 +0200
From:   Helge Deller <deller@....de>
To:     Thomas Zimmermann <tzimmermann@...e.de>, daniel@...ll.ch,
        javierm@...hat.com, sam@...nborg.org, linux-fbdev@...r.kernel.org,
        dri-devel@...ts.freedesktop.org
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/7] fbdev/core: Build fb_logo iff CONFIG_LOGO has been
 selected

On 8/29/23 16:15, Thomas Zimmermann wrote:
> Only build fb_logo.c if CONFIG_LOGO has been selected. Otherwise
> provide empty implementations of the contained interfaces and avoid
> using the exported variables.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@...e.de>
...
> diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
> index f157a5a1dffc..24b038510a71 100644
> --- a/drivers/video/fbdev/core/fbcon.c
> +++ b/drivers/video/fbdev/core/fbcon.c
> @@ -474,15 +474,19 @@ static int __init fb_console_setup(char *this_opt)
>
>   		if (!strncmp(options, "logo-pos:", 9)) {
>   			options += 9;
> +#ifdef CONFIG_LOGO
>   			if (!strcmp(options, "center"))
>   				fb_center_logo = true;
> +#endif

IMHO, *sometimes* it makes sense to not use #ifdef and code it instead like this:
   			if (IS_ENABLED(CONFIG_LOGO) &&
			    !strcmp(options, "center"))
...
That way the compiler will optimize that code away as well, but in
addition it will compile-check that you have correct coding independend
if CONFIG_LOGO is set or not.

>   			continue;
>   		}
>
>   		if (!strncmp(options, "logo-count:", 11)) {
>   			options += 11;
> +#ifdef CONFIG_LOGO
>   			if (*options)
>   				fb_logo_count = simple_strtol(options, &options, 0);
> +#endif

same here.

Helge