[PATCH] fbdev: Fix incorrect unaligned access in little-endian machines

The drawing function cfbfillrect does not work correctly when access is not
unsigned-long aligned.  It manifests as extra lines of pixels that are not
complete drawn.  Reversing the shift operator solves the problem, so I would
presume that this bug would manifest only on little endian machines.  The
function cfbcopyarea may also have this bug.

Aligned access should present no problems.

Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/video/cfbcopyarea.c b/drivers/video/cfbcopyarea.c
index cdc71572cf35..74415325b016 100644
--- a/drivers/video/cfbcopyarea.c
+++ b/drivers/video/cfbcopyarea.c
@@ -64,8 +64,8 @@ bitcpy(unsigned long __iomem *dst, int dst_idx, const unsigned long __iomem *src
         int const shift = dst_idx-src_idx;
         int left, right;
 
-        first = ~0UL >> dst_idx;
-        last = ~(~0UL >> ((dst_idx+n) % bits));
+        first = FB_SHIFT_HIGH(~0UL, dst_idx);
+        last = ~(FB_SHIFT_HIGH(~0UL, (dst_idx+n) % bits));
 
         if (!shift) {
                 // Same alignment for source and dest
@@ -216,8 +216,8 @@ bitcpy_rev(unsigned long __iomem *dst, int dst_idx, const unsigned long __iomem
 
         shift = dst_idx-src_idx;
 
-        first = ~0UL << (bits - 1 - dst_idx);
-        last = ~(~0UL << (bits - 1 - ((dst_idx-n) % bits)));
+        first = FB_SHIFT_LOW(~0UL, bits - 1 - dst_idx);
+        last = ~(FB_SHIFT_LOW(~0UL, bits - 1 - ((dst_idx-n) % bits)));
 
         if (!shift) {
                 // Same alignment for source and dest