linux-kernel - Re: [PATCH] fbmem: really support wildcard video=options for all fbdev drivers

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Message-ID: <52CD58C8.3040703@ti.com>
Date:	Wed, 8 Jan 2014 15:55:20 +0200
From:	Tomi Valkeinen <tomi.valkeinen@...com>
To:	Olaf Hering <olaf@...fle.de>
CC:	<plagnioj@...osoft.com>, <linux-fbdev@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] fbmem: really support wildcard video=options for all
 fbdev drivers

On 2013-12-15 22:40, Olaf Hering wrote:
> Documentation/fb/modedb.txt states that video=option should be
> considered a global option. But video_setup and fb_get_options are not
> coded that way. Instead its required to boot with video=driver:option to
> set a given option in drvier.  This is cumbersome because it requires to
> know in advance which driver will be active for a given board/kernel.
> 
> The following patch implements the documented catchall for the fbdev
> drivers. It is now possible to boot with video=XxY without the need to
> know the active driver in advance. The specific case it tries to fix is
> syslinux in the SUSE installer which offers a menu to set a display
> resolution. Right now this just appends the vga= option the kernel. But
> in addition to vga= it should be possible to pass a generic video=XxY
> for all framebuffer/drm drivers. With this change forcing a certain
> window size of VM displays is now much easier.
> 
> Today the video= option is stored in a global fb_mode_option. But
> unfortunately only drm uses it.
> 
> Note: this change introduces a small memleak if video=option is actually
> used because fb_mode_option is const. Most drivers use strsep to get to
> individual options. This could be fixed in a followup patch which always
> releases the option string in every caller of fb_get_options.
> 
> Signed-off-by: Olaf Hering <olaf@...fle.de>
> ---
>  drivers/video/fbmem.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
> index 010d191..cde4619 100644
> --- a/drivers/video/fbmem.c
> +++ b/drivers/video/fbmem.c
> @@ -1930,6 +1930,9 @@ int fb_get_options(const char *name, char **option)
>  				options = opt + name_len + 1;
>  		}
>  	}
> +	/* No match, pass global option */
> +	if (!options && option && fb_mode_option)
> +		options = kstrdup(fb_mode_option, GFP_KERNEL);
>  	if (options && !strncmp(options, "off", 3))
>  		retval = 1;
>  
> 

Queued for 3.14.

 Tomi



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