[src/trunk]: src/sys/dev/wscons clarify how backlight control ioctl()s are su...

[macallan <macallan%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/ce327225cc90
branches:  trunk
changeset: 757884:ce327225cc90
user:      macallan <macallan%NetBSD.org@localhost>
date:      Sat Oct 02 00:52:02 2010 +0000

description:
clarify how backlight control ioctl()s are supposed to work
TODO: adapt r128fb and radeonfb

diffstat:

 sys/dev/wscons/wsconsio.h |  11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diffs (25 lines):

diff -r 7ffec3c82f18 -r ce327225cc90 sys/dev/wscons/wsconsio.h
--- a/sys/dev/wscons/wsconsio.h Fri Oct 01 21:08:27 2010 +0000
+++ b/sys/dev/wscons/wsconsio.h Sat Oct 02 00:52:02 2010 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: wsconsio.h,v 1.92 2009/12/31 05:08:05 macallan Exp $ */
+/* $NetBSD: wsconsio.h,v 1.93 2010/10/02 00:52:02 macallan Exp $ */
 
 /*
  * Copyright (c) 1996, 1997 Christopher G. Demetriou.  All rights reserved.
@@ -442,7 +442,14 @@
 };
 #define        _O_WSDISPLAYIO_SETKEYBOARD      _IOWR('W', 81, struct wsdisplay_kbddata)
 
-/* Misc control.  Not applicable to all display types. */
+/*
+ * Misc control.  Not applicable to all display types.
+ * - WSDISPLAYIO_PARAM_BACKLIGHT should be an on/off switch for screensavers,
+ *   it should turn the display dark / turn the backlight off without changing
+ *   the brightness value so screensavers and such can just flip the switch
+ *   without caring about actual brightness settings
+ * - WSDISPLAYIO_PARAM_BRIGHTNESS should set display / backlight brightness
+ */
 struct wsdisplay_param {
        int param;
 #define        WSDISPLAYIO_PARAM_BACKLIGHT     1