linux-kernel - [PATCH] Re: fbcon: replace mono

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Date:	Mon, 08 Sep 2008 19:25:18 -0700
From:	q-newsgroup@...ea.com
To:	linux-kernel@...r.kernel.org
Subject: [PATCH] Re: fbcon: replace mono_col macro with static inline


Commit 22af89aa0c0b4012a7431114a340efd3665a7617 changed the order of
operations for computing monochrome color values. This generates
0xffff000f instead of 0x0000000f for a 4 bit monochrome color, leading
to image corruption if it is passed to cfb_imageblit or other similar
functions.
Here's a quick patch to fix it up.
David Winn

PS: Please CC me with any replies. Thanks

diff --git a/drivers/video/console/fbcon.h
b/drivers/video/console/fbcon.h
index a6e38e9..89a3468 100644
--- a/drivers/video/console/fbcon.h
+++ b/drivers/video/console/fbcon.h
@@ -110,7 +110,7 @@ static inline int mono_col(const struct fb_info
*info)
        __u32 max_len;
        max_len = max(info->var.green.length, info->var.red.length);
        max_len = max(info->var.blue.length, max_len);
-       return ~(0xfff << (max_len & 0xff));
+       return (~(0xfff << max_len)) & 0xff;
 }

 static inline int attr_col_ec(int shift, struct vc_data *vc,

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