[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
diff --git a/drivers/video/cfbfillrect.c b/drivers/video/cfbfillrect.c
index 167d931..e5ff62e 100644
--- a/drivers/video/cfbfillrect.c
+++ b/drivers/video/cfbfillrect.c
@@ -110,8 +110,8 @@
if (!n)
return;
- 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 (dst_idx+n <= bits) {
// Single word
@@ -167,8 +167,8 @@
if (!n)
return;
- 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 (dst_idx+n <= bits) {
// Single word
@@ -221,8 +221,8 @@
if (!n)
return;
- 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 (dst_idx+n <= bits) {
// Single word
@@ -290,8 +290,8 @@
if (!n)
return;
- 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 (dst_idx+n <= bits) {
// Single word
diff --git a/drivers/video/cfbimgblt.c b/drivers/video/cfbimgblt.c
index 7a01742..910e233 100644
--- a/drivers/video/cfbimgblt.c
+++ b/drivers/video/cfbimgblt.c
@@ -76,18 +76,6 @@
#define FB_WRITEL fb_writel
#define FB_READL fb_readl
-#if defined (__BIG_ENDIAN)
-#define LEFT_POS(bpp) (32 - bpp)
-#define SHIFT_HIGH(val, bits) ((val) >> (bits))
-#define SHIFT_LOW(val, bits) ((val) << (bits))
-#define BIT_NR(b) (7 - (b))
-#else
-#define LEFT_POS(bpp) (0)
-#define SHIFT_HIGH(val, bits) ((val) << (bits))
-#define SHIFT_LOW(val, bits) ((val) >> (bits))
-#define BIT_NR(b) (b)
-#endif
-
static inline void color_imageblit(const struct fb_image *image,
struct fb_info *p, u8 __iomem *dst1,
u32 start_index,
@@ -109,7 +97,7 @@
val = 0;
if (start_index) {
- u32 start_mask = ~(SHIFT_HIGH(~(u32)0, start_index));
+ u32 start_mask = ~(FB_SHIFT_HIGH(~(u32)0, start_index));
val = FB_READL(dst) & start_mask;
shift = start_index;
}
@@ -119,20 +107,20 @@
color = palette[*src];
else
color = *src;
- color <<= LEFT_POS(bpp);
- val |= SHIFT_HIGH(color, shift);
+ color <<= FB_LEFT_POS(bpp);
+ val |= FB_SHIFT_HIGH(color, shift);
if (shift >= null_bits) {
FB_WRITEL(val, dst++);
val = (shift == null_bits) ? 0 :
- SHIFT_LOW(color, 32 - shift);
+ FB_SHIFT_LOW(color, 32 - shift);
}
shift += bpp;
shift &= (32 - 1);
src++;
}
if (shift) {
- u32 end_mask = SHIFT_HIGH(~(u32)0, shift);
+ u32 end_mask = FB_SHIFT_HIGH(~(u32)0, shift);
FB_WRITEL((FB_READL(dst) & end_mask) | val, dst);
}
@@ -162,8 +150,8 @@
u32 i, j, l;
dst2 = (u32 __iomem *) dst1;
- fgcolor <<= LEFT_POS(bpp);
- bgcolor <<= LEFT_POS(bpp);
+ fgcolor <<= FB_LEFT_POS(bpp);
+ bgcolor <<= FB_LEFT_POS(bpp);
for (i = image->height; i--; ) {
shift = val = 0;
@@ -174,21 +162,21 @@
/* write leading bits */
if (start_index) {
- u32 start_mask = ~(SHIFT_HIGH(~(u32)0, start_index));
+ u32 start_mask = ~(FB_SHIFT_HIGH(~(u32)0,start_index));
val = FB_READL(dst) & start_mask;
shift = start_index;
}
while (j--) {
l--;
- color = (*s & 1 << (BIT_NR(l))) ? fgcolor : bgcolor;
- val |= SHIFT_HIGH(color, shift);
+ color = (*s & 1 << (FB_BIT_NR(l))) ? fgcolor : bgcolor;
+ val |= FB_SHIFT_HIGH(color, shift);
/* Did the bitshift spill bits to the next long? */
if (shift >= null_bits) {
FB_WRITEL(val, dst++);
val = (shift == null_bits) ? 0 :
- SHIFT_LOW(color,32 - shift);
+ FB_SHIFT_LOW(color,32 - shift);
}
shift += bpp;
shift &= (32 - 1);
@@ -197,7 +185,7 @@
/* write trailing bits */
if (shift) {
- u32 end_mask = SHIFT_HIGH(~(u32)0, shift);
+ u32 end_mask = FB_SHIFT_HIGH(~(u32)0, shift);
FB_WRITEL((FB_READL(dst) & end_mask) | val, dst);
}
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
*/