[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/include/linux/fb.h b/include/linux/fb.h
index dab3a4d..a973be2 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -835,6 +835,18 @@
#endif
+#if defined (__BIG_ENDIAN)
+#define FB_LEFT_POS(bpp) (32 - bpp)
+#define FB_SHIFT_HIGH(val, bits) ((val) >> (bits))
+#define FB_SHIFT_LOW(val, bits) ((val) << (bits))
+#define FB_BIT_NR(b) (7 - (b))
+#else
+#define FB_LEFT_POS(bpp) (0)
+#define FB_SHIFT_HIGH(val, bits) ((val) << (bits))
+#define FB_SHIFT_LOW(val, bits) ((val) >> (bits))
+#define FB_BIT_NR(b) (b)
+#endif
+
/*
* `Generic' versions of the frame buffer device operations
*/