On Sun, 2002-12-29 at 09:16, James Simmons wrote:
>
> > The text is written as if it's thinking about handling 64-bit
> > unsigned long, but it doesn't. The tables that map bits to
> > pixels are completely unprepared for this.
> >
> > I thought about widening the tables, but I thought they'd get
> > unreasonably large. There's no reason not to go ahead and
> > handle this 32-bits at a time.
>
> I thought the tables would come back to haunt us. The only reason the
> tables where introduced was for speed enhancements. I reason the code is
> extra complex was so you could pass 64 bits of data across the bus. I
> still like to see that happen still. What do you think?
>
Only fast_imageblit() should be affected. color_imageblit() and
slow_imageblit() will not be affected.
fast_imageblit() is used only for 8, 16 and 32 bpp. We can remove
fast_imageblit() and just use slow_imageblit() for all color depths, but
it will suffer a significant slowdown.
Or we can change fast_imageblit() to always access the framebuffer
memory 32-bits at a time. The attached patch should fix this.
Tony
diff -Naur linux-2.5.42/drivers/video/cfbimgblt.c linux/drivers/video/cfbimgblt.c
--- linux-2.5.42/drivers/video/cfbimgblt.c 2002-12-29 14:44:04.000000000 +0000
+++ linux/drivers/video/cfbimgblt.c 2002-12-29 14:44:23.000000000 +0000
@@ -88,11 +88,13 @@
#if defined (__BIG_ENDIAN)
#define LEFT_POS(bpp) (BITS_PER_LONG - bpp)
+#define LEFT_POS32(bpp) (32 - bpp)
#define NEXT_POS(pos, bpp) ((pos) -= (bpp))
#define SHIFT_HIGH(val, bits) ((val) >> (bits))
#define SHIFT_LOW(val, bits) ((val) << (bits))
#else
#define LEFT_POS(bpp) (0)
+#define LEFT_POS32(bpp) (0)
#define NEXT_POS(pos, bpp) ((pos) += (bpp))
#define SHIFT_HIGH(val, bits) ((val) << (bits))
#define SHIFT_LOW(val, bits) ((val) >> (bits))
@@ -223,25 +225,25 @@
}
static inline void fast_imageblit(struct fb_image *image, struct fb_info *p, u8 *dst1,
- unsigned long fgcolor, unsigned long bgcolor)
+ u32 fgcolor, u32 bgcolor)
{
int i, j, k, l = 8, n;
- unsigned long bit_mask, end_mask, eorx;
- unsigned long fgx = fgcolor, bgx = bgcolor, pad, bpp = p->var.bits_per_pixel;
- unsigned long tmp = (1 << bpp) - 1;
- unsigned long ppw = BITS_PER_LONG/bpp, ppos;
- unsigned long *dst;
+ u32 bit_mask, end_mask, eorx;
+ u32 fgx = fgcolor, bgx = bgcolor, pad, bpp = p->var.bits_per_pixel;
+ u32 tmp = (1 << bpp) - 1;
+ u32 ppw = 32/bpp, ppos;
+ u32 *dst;
u32 *tab = NULL;
char *src = image->data;
- switch (ppw) {
- case 4:
+ switch (bpp) {
+ case 8:
tab = cfb_tab8;
break;
- case 2:
+ case 16:
tab = cfb_tab16;
break;
- case 1:
+ case 32:
tab = cfb_tab32;
break;
}
@@ -263,17 +265,17 @@
k = image->width/ppw;
for (i = image->height; i--; ) {
- dst = (unsigned long *) dst1;
+ dst = (u32 *) dst1;
for (j = k; j--; ) {
l -= ppw;
end_mask = tab[(*src >> l) & bit_mask];
- FB_WRITEL((end_mask & eorx)^bgx, dst++);
+ fb_writel((end_mask & eorx)^bgx, dst++);
if (!l) { l = 8; src++; }
}
if (n) {
end_mask = 0;
- ppos = LEFT_POS(bpp);
+ ppos = LEFT_POS32(bpp);
for (j = n; j > 0; j--) {
l--;
if (*src & (1 << l))
@@ -281,7 +283,7 @@
NEXT_POS(ppos, bpp);
if (!l) { l = 8; src++; }
}
- FB_WRITEL((end_mask & eorx)^bgx, dst++);
+ fb_writel((end_mask & eorx)^bgx, dst++);
}
l -= pad;
dst1 += p->fix.line_length;
@@ -337,7 +339,7 @@
if (BITS_PER_LONG % bpp == 0 && !start_index && !pitch_index &&
bpp >= 8 && bpp <= 32 && (image->width & 7) == 0)
- fast_imageblit(image, p, dst1, fgcolor, bgcolor);
+ fast_imageblit(image, p, dst1, (u32) fgcolor, (u32) bgcolor);
else
slow_imageblit(image, p, dst1, fgcolor, bgcolor, start_index, pitch_index);
}
-
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This archive was generated by hypermail 2b29 : Tue Dec 31 2002 - 22:00:13 EST