Fix clearing of vertical margins

Whenever the font width does not divide the x resolution, the remainder of this division is a vertical margin at right of the screen. Whatever the video memory contains in that margin is displayed.

This patch corrects this behaviour. There is no performance impact as long as there is no vertical margin as fbcon_clear_margins() and bit_clear_margins() only execute additional code if really necessary.

I think this patch should be applied before 2.6.15-final.

diff -uprN -X linux/Documentation/dontdiff -x '*.bak' -x '*.ctx' linuxorig/drivers/video/console/fbcon.c linux/drivers/video/console/fbcon.c
@@ -1399,7 +1399,7 @@ static __inline__ void ypan_up(struct vc

	ops->var.yoffset = p->yscroll * vc->vc_font.height;
	ops->var.vmode &= ~FB_VMODE_YWRAP;
	ops->update_start(info);
-	fbcon_clear_margins(vc, 1);
+	fbcon_clear_margins(vc, 0);
	scrollback_max += count;
	if (scrollback_max > scrollback_phys_max)
		scrollback_max = scrollback_phys_max;
@@ -1426,7 +1426,7 @@ static __inline__ void ypan_up_redraw(st
	ops->var.yoffset = p->yscroll * vc->vc_font.height;
	ops->var.vmode &= ~FB_VMODE_YWRAP;
	ops->update_start(info);
-	fbcon_clear_margins(vc, 1);
+	fbcon_clear_margins(vc, 0);
	scrollback_max += count;
	if (scrollback_max > scrollback_phys_max)
		scrollback_max = scrollback_phys_max;
@@ -1450,7 +1450,7 @@ static __inline__ void ypan_down(struct 
	ops->var.yoffset = p->yscroll * vc->vc_font.height;
	ops->var.vmode &= ~FB_VMODE_YWRAP;
	ops->update_start(info);
-	fbcon_clear_margins(vc, 1);
+	fbcon_clear_margins(vc, 0);
	scrollback_max -= count;
	if (scrollback_max < 0)
		scrollback_max = 0;
@@ -1477,7 +1477,7 @@ static __inline__ void ypan_down_redraw(
	ops->var.yoffset = p->yscroll * vc->vc_font.height;
	ops->var.vmode &= ~FB_VMODE_YWRAP;
	ops->update_start(info);
-	fbcon_clear_margins(vc, 1);
+	fbcon_clear_margins(vc, 0);
	scrollback_max -= count;
	if (scrollback_max < 0)
		scrollback_max = 0;

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NAK. The right margin is cleared just once on an fbcon_switch (entire yres_virtual). The right margin should remain cleared until another fbcon_switch happens so it's not necessary to clear the right margins again.

Tony

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You are right. I hit an internal limit of the cyberblade engine.

cu,
knut

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