linux-kernel - Re: [PATCH linux-next] tty: Disable default console blanking interval

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Date:   Wed, 22 Mar 2017 10:14:45 -0400
From:   "Austin S. Hemmelgarn" <ahferroin7@...il.com>
To:     Tim Gardner <tim.gardner@...onical.com>,
        linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>,
        Adam Borowski <kilobyte@...band.pl>,
        Scot Doyle <lkml14@...tdoyle.com>
Subject: Re: [PATCH linux-next] tty: Disable default console blanking interval

On 2017-03-22 09:50, Tim Gardner wrote:
> BugLink: http://bugs.launchpad.net/bugs/869017
>
> Signed-off-by: Tim Gardner <tim.gardner@...onical.com>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: Jiri Slaby <jslaby@...e.com>
> Cc: Adam Borowski <kilobyte@...band.pl>
> Cc: Scot Doyle <lkml14@...tdoyle.com>
> ---
>
> I'm not particularly knowledgable about console issues. Is a blaknking interval
> relevant in a post CRT world ? The argument in the bug description seems
> compelling.
Burn-in still happens on at least LCD screens (not sure about anything 
else except DLP, where it doesn't happen unless it's a really crappy 
display), but on many of those it happens regardless of the contents of 
the display (I've actually got an old LCD display where the image is 
constantly dark because of having displayed so many hours of a black 
screen), but displaying a black screen instead of powering off the 
display doesn't really save any power on most modern displays and the 
fact that the screen isn't un-blanked when the kernel crashes is a 
pretty compelling argument against having it enabled by default IMO.
>
>  drivers/tty/vt/vt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
> index 5c4933b..9c99452 100644
> --- a/drivers/tty/vt/vt.c
> +++ b/drivers/tty/vt/vt.c
> @@ -181,7 +181,7 @@ int console_blanked;
>
>  static int vesa_blank_mode; /* 0:none 1:suspendV 2:suspendH 3:powerdown */
>  static int vesa_off_interval;
> -static int blankinterval = 10*60;
> +static int blankinterval;
>  core_param(consoleblank, blankinterval, int, 0444);
>
>  static DECLARE_WORK(console_work, console_callback);
>