From e122d55965fb3479976180d17141ce85f9342724 Mon Sep 17 00:00:00 2001
From: marschap <marschap@users.sourceforge.net>
Date: Sat, 8 Mar 2008 18:23:07 +0000
Subject: [PATCH] don't allow turning the backlight on if have_backlight == 0

---
 server/drivers/hd44780.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/server/drivers/hd44780.c b/server/drivers/hd44780.c
index 04eb6f6..a7e9994 100644
--- a/server/drivers/hd44780.c
+++ b/server/drivers/hd44780.c
@@ -849,6 +849,11 @@ HD44780_backlight(Driver *drvthis, int on)
 {
 	PrivateData *p = (PrivateData *) drvthis->private_data;
 
+	// not sure if this is the correct solution.
+	// alternative: return immediately	
+	if (!p->have_backlight)
+		on = 0;
+
 	if (p->hd44780_functions->backlight != NULL)
 		p->hd44780_functions->backlight(p, on);
 }