Re: [PATCH] vt: do not update when the console is blanked

[Andrew Morton <akpm@linux-foundation.org>]

(cc linux-fbdev-devel)

On Fri, 11 Jul 2008 15:50:18 +0100 Stefano Stabellini <stefano.stabellini@eu.citrix.com> wrote:

> Hi all,
> vt.c DO_UPDATE macro checks if the console is visible but doesn't check if
> the console is blanked.
> In fact updating fbcon while the console is blanked is not only unnecessary
> but can even cause screen corruption.
> Therefore I am adding a simple check on console_blanked in DO_UPDATE.
> 
> Signed-off-by: stefano.stabellini@eu.citrix.com
> 
> ---
> 
> diff --git a/drivers/char/vt.c b/drivers/char/vt.c
> index 935f1c2..8d4bd3c 100644
> --- a/drivers/char/vt.c
> +++ b/drivers/char/vt.c
> @@ -261,7 +261,7 @@ static void notify_update(struct vc_data *vc)
>  #ifdef VT_BUF_VRAM_ONLY
>  #define DO_UPDATE(vc)	0
>  #else
> -#define DO_UPDATE(vc)	CON_IS_VISIBLE(vc)
> +#define DO_UPDATE(vc)	(CON_IS_VISIBLE(vc) && !console_blanked)
>  #endif
>  
>  static inline unsigned short *screenpos(struct vc_data *vc, int offset, int viewed)
>