Messages in this thread Patch in this message | | | Date | Mon, 06 Nov 2006 10:28:16 +0100 | Subject | [PATCH] fbcon: ReRe-fix little-endian bogosity in slow_imageblit() | From | Franck Bui-Huu <> |
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From: Franck Bui-Huu <fbuihuu@gmail.com>
It seems that this piece of code has already been fixed twice...
The first fix has been made by the following commit:
81d3e147ec9ffc6ef04b5f05afa4bef22487b32b
by introducing FB_BIT_NR() macro to fix a 'potential' endianess bug. It appears that change was broken for big endian platforms, but I suspect it was for little-endian ones too.
Then a second fix has been made to fix the previous change for big-endian platform, see commit:
a536093a2f07007aa572e922752b7491b9ea8ff2
This commit actually reverted the first fix and thus makes the big-endian case works but leaves the little-endian case broken. Therefore it seems that the very first state was broken only on little-endian platform...
This patch is the third and hopefully the last attempt to fix this bug correctly. It restores the first fix _and_ swaps the little-endian and bit-endian implementations of FB_BIT_NR().
Now, it should work for both endianness but has been tested on little-endian machine only.
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com> ---
Same patch with change log updated.
drivers/video/cfbimgblt.c | 4 ++-- include/linux/fb.h | 2 ++ 2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/video/cfbimgblt.c b/drivers/video/cfbimgblt.c index 51d3538..8f47bf4 100644 --- a/drivers/video/cfbimgblt.c +++ b/drivers/video/cfbimgblt.c @@ -168,7 +168,7 @@ static inline void slow_imageblit(const while (j--) { l--; - color = (*s & (1 << l)) ? fgcolor : bgcolor; + color = (*s & (1 << FB_BIT_NR(l))) ? fgcolor : bgcolor; val |= FB_SHIFT_HIGH(color, shift); /* Did the bitshift spill bits to the next long? */ @@ -258,7 +258,7 @@ static inline void fast_imageblit(const s += spitch; } } - + void cfb_imageblit(struct fb_info *p, const struct fb_image *image) { u32 fgcolor, bgcolor, start_index, bitstart, pitch_index = 0; diff --git a/include/linux/fb.h b/include/linux/fb.h index 3e69241..6ca18b8 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -854,10 +854,12 @@ struct fb_info { #endif #if defined (__BIG_ENDIAN) +#define FB_BIT_NR(b) (b) #define FB_LEFT_POS(bpp) (32 - bpp) #define FB_SHIFT_HIGH(val, bits) ((val) >> (bits)) #define FB_SHIFT_LOW(val, bits) ((val) << (bits)) #else +#define FB_BIT_NR(b) (7 - (b)) #define FB_LEFT_POS(bpp) (0) #define FB_SHIFT_HIGH(val, bits) ((val) << (bits)) #define FB_SHIFT_LOW(val, bits) ((val) >> (bits)) -- 1.4.3.4 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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