[3.8.y.z extended stable] Patch "mach64: fix cursor when character width is not a multiple of 8 pixels" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    mach64: fix cursor when character width is not a multiple of 8 pixels

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.22.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 3a422948ef67409c39a10e39375f13ca99f7046a Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka at redhat.com>
Date: Thu, 23 Jan 2014 14:41:59 -0500
Subject: mach64: fix cursor when character width is not a multiple of 8 pixels

commit 43751a1b8ee2e70ce392bf31ef3133da324e68b3 upstream.

This patch fixes the hardware cursor on mach64 when font width is not a
multiple of 8 pixels.

If you load such a font, the cursor is expanded to the next 8-byte
boundary and a part of the next character after the cursor is not
visible.
For example, when you load a font with 12-pixel width, the cursor width
is 16 pixels and when the cursor is displayed, 4 pixels of the next
character are not visible.

The reason is this: atyfb_cursor is called with proper parameters to
load an image that is 12-pixel wide. However, the number is aligned on
the next 8-pixel boundary on the line
"unsigned int width = (cursor->image.width + 7) >> 3;" and the whole
function acts as it is was loading a 16-pixel image.

This patch fixes it so that the value written to the framebuffer is
padded with 0xaaaa (the transparent pattern) when the image size it not
a multiple of 8 pixels. The transparent pattern causes that the cursor
will not interfere with the next character.

Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/video/aty/mach64_cursor.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/video/aty/mach64_cursor.c b/drivers/video/aty/mach64_cursor.c
index 95ec042..0fe02e2 100644
--- a/drivers/video/aty/mach64_cursor.c
+++ b/drivers/video/aty/mach64_cursor.c
@@ -5,6 +5,7 @@
 #include <linux/fb.h>
 #include <linux/init.h>
 #include <linux/string.h>
+#include "../fb_draw.h"

 #include <asm/io.h>

@@ -157,24 +158,33 @@ static int atyfb_cursor(struct fb_info *info, struct fb_cursor *cursor)

 	    for (i = 0; i < height; i++) {
 		for (j = 0; j < width; j++) {
+			u16 l = 0xaaaa;
 			b = *src++;
 			m = *msk++;
 			switch (cursor->rop) {
 			case ROP_XOR:
 			    // Upper 4 bits of mask data
-			    fb_writeb(cursor_bits_lookup[(b ^ m) >> 4], dst++);
+			    l = cursor_bits_lookup[(b ^ m) >> 4] |
 			    // Lower 4 bits of mask
-			    fb_writeb(cursor_bits_lookup[(b ^ m) & 0x0f],
-				      dst++);
+				    (cursor_bits_lookup[(b ^ m) & 0x0f] << 8);
 			    break;
 			case ROP_COPY:
 			    // Upper 4 bits of mask data
-			    fb_writeb(cursor_bits_lookup[(b & m) >> 4], dst++);
+			    l = cursor_bits_lookup[(b & m) >> 4] |
 			    // Lower 4 bits of mask
-			    fb_writeb(cursor_bits_lookup[(b & m) & 0x0f],
-				      dst++);
+				    (cursor_bits_lookup[(b & m) & 0x0f] << 8);
 			    break;
 			}
+			/*
+			 * If cursor size is not a multiple of 8 characters
+			 * we must pad it with transparent pattern (0xaaaa).
+			 */
+			if ((j + 1) * 8 > cursor->image.width) {
+				l = comp(l, 0xaaaa,
+				    (1 << ((cursor->image.width & 7) * 2)) - 1);
+			}
+			fb_writeb(l & 0xff, dst++);
+			fb_writeb(l >> 8, dst++);
 		}
 		dst += offset;
 	    }
--
1.9.1