Re: [PATCH] 2.5.70: add comment about console LCD backlight issues

From: Pavel Machek (pavel@suse.cz)
Date: Wed Jun 04 2003 - 17:03:56 EST


Hi!

> a lot of people seem to be confused about (non-working) notebook display
> blanking, so...
>
> - add verbose explanation about the whole notebook screen blanking situation
> and a possible development direction to prominent place

Please submit it to Rusty trivial patch monkey Russell
<trivial@rustcorp.com.au>.

> I might actually be tempted to unify graphics hardware backlight handling
> myself, since having a console that doesn't shut down the backlight properly
> is mildly annoying...

Yep, solving that somehow would be good.

> Patch against vanilla 2.5.70.
>
> Andreas Mohr
>
> diff -urN linux-2.5.70.orig/drivers/video/console/vgacon.c linux-2.5.70/drivers/video/console/vgacon.c
> --- linux-2.5.70.orig/drivers/video/console/vgacon.c 2003-05-28 17:57:07.000000000 +0200
> +++ linux-2.5.70/drivers/video/console/vgacon.c 2003-05-29 03:13:53.000000000 +0200
> @@ -661,6 +661,22 @@
> }
> }
>
> +/*
> + * vgacon_blank() is able to simply blank the screen, or to even switch
> + * the monitor off in case of "Green", "Energy Star" monitors
> + * (by switching off the sync signals using VESA mechanisms).
> + * However, it is NOT able to switch off the *backlight* of (most?)
> notebooks.

Acurate, AFAICS. Why can't that stupid notebook manufacturers make it
turn backlight off on VESA blank?!

                                                                Pavel

-- 
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]
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