From mboxrd@z Thu Jan  1 00:00:00 1970
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: Console rotation problems
Date: Thu, 24 Nov 2005 14:05:42 +1100
Message-ID: <1132801542.26560.402.camel@gaston>
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Cc: Andrew Morton <akpm@osdl.org>, Linux Fbdev development list <linux-fbdev-devel@lists.sourceforge.net>, Linux Kernel list <linux-kernel@vger.kernel.org>

Remove bogus usage of test/set_bit() from fbcon rotation code and just
manipulate the bits directly. This fixes an oops on powerpc among others
and should be faster. Seems to work fine on the G5 here.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

And here is the fix. Tony, did I miss something ?

Index: linux-serialfix/drivers/video/console/fbcon_rotate.h
===================================================================
--- linux-serialfix.orig/drivers/video/console/fbcon_rotate.h	2005-11-23 11:07:23.000000000 +1100
+++ linux-serialfix/drivers/video/console/fbcon_rotate.h	2005-11-24 14:02:22.000000000 +1100
@@ -21,21 +21,13 @@
         (s == SCROLL_REDRAW || s == SCROLL_MOVE || !(i)->fix.xpanstep) ? \
         (i)->var.xres : (i)->var.xres_virtual; })
 
-/*
- * The bitmap is always big endian
- */
-#if defined(__LITTLE_ENDIAN)
-#define FBCON_BIT(b) (7 - (b))
-#else
-#define FBCON_BIT(b) (b)
-#endif
 
 static inline int pattern_test_bit(u32 x, u32 y, u32 pitch, const char *pat)
 {
 	u32 tmp = (y * pitch) + x, index = tmp / 8,  bit = tmp % 8;
 
 	pat +=index;
-	return (test_bit(FBCON_BIT(bit), (void *)pat));
+	return (*pat) & (0x80 >> bit);
 }
 
 static inline void pattern_set_bit(u32 x, u32 y, u32 pitch, char *pat)
@@ -43,7 +35,8 @@ static inline void pattern_set_bit(u32 x
 	u32 tmp = (y * pitch) + x, index = tmp / 8, bit = tmp % 8;
 
 	pat += index;
-	set_bit(FBCON_BIT(bit), (void *)pat);
+
+	(*pat) |= 0x80 >> bit;
 }
 
 static inline void rotate_ud(const char *in, char *out, u32 width, u32 height)
Index: linux-serialfix/drivers/video/console/fbcon_ccw.c
===================================================================
--- linux-serialfix.orig/drivers/video/console/fbcon_ccw.c	2005-11-15 11:54:14.000000000 +1100
+++ linux-serialfix/drivers/video/console/fbcon_ccw.c	2005-11-24 14:03:48.000000000 +1100
@@ -34,7 +34,7 @@ static inline void ccw_update_attr(u8 *d
 		msk <<= (8 - mod);
 
 	if (offset > mod)
-		set_bit(FBCON_BIT(7), (void *)&msk1);
+		msk1 |= 0x01;
 
 	for (i = 0; i < vc->vc_font.width; i++) {
 		for (j = 0; j < width; j++) {