From mboxrd@z Thu Jan 1 00:00:00 1970 From: Franck Bui-Huu Subject: [PATCH] fbcon: ReRe-fix little-endian bogosity in slow_imageblit() Date: Mon, 06 Nov 2006 10:28:16 +0100 Message-ID: <454F0030.80101@innova-card.com> References: <454B5866.6000207@innova-card.com> <20061103105857.874f566c.akpm@osdl.org> Reply-To: Franck Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: Cc: linux-kernel@vger.kernel.org, linux-fbdev-devel@lists.sourceforge.net, adaplas@pol.net, gregkh@suse.de From: Franck Bui-Huu 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 --- 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