[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>
diff --git a/drivers/video/cfbcopyarea.c b/drivers/video/cfbcopyarea.c
index cdc7157..7441532 100644
--- a/drivers/video/cfbcopyarea.c
+++ b/drivers/video/cfbcopyarea.c
@@ -64,8 +64,8 @@
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 @@
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