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SubjectRe: [Linux-fbdev-devel] fbmem: is bootup logo broken for monochrome LCD ?

I'm going away for the weekend so you wouldn't here from me but I will
look over the code and test it out.

On Wed, 22 Nov 2006, Franck Bui-Huu wrote:

> James Simmons wrote:
> > Lets look at the new code that I have done with your above parameters.
> >
> > for (i = image->height; i--; ) {
> > shift = val = 0;
> > n = image->width;
> > dst = (u32 __iomem *) dst1;
> >
> > while (n--) {
> > if (!s) { src++; s = 32; }
> > s -= 1;
> > color = (swapb32p(src) & (1 << s)) ? 1 : 0;
> > val |= color << shift;
> >
> > /* Did the bitshift spill bits to the next long? */
> > if (shift >= 31) {
> > FB_WRITEL(val, dst++);
> > val = (shift == 31) ? 0 :(color >> (32 - shift));
> > }
> > shift += 1;
> > shift &= (32 - 1);
> > }
> >
> > [ ...]
> >
> > with 's' taking values from 31 to 0, and 'shift' taking values from 0 to
> > 31. In the case of bits_per_pixel = 1 we have
> >
> > s -= 1;
> > color = (swapb32p(src) & (1 << s)) ? 1 : 0;
> > val |= color << shift;
>
> I suppose here that you meant 'swab32p' instead of 'swapb32p'. I can't
> find any definition of 'swapb32p' and in your last patch you sent you
> is using 'swab32p' which converts a 32-bits little endian word into a
> 32-bits big endian one.
>
> >
> > which reduces to val = color;
> >
> > I'm I seeing it wrong?
>
> Well, I would say yes you are. If src = { 0xa3, 0x30, 0xef, 0x72 ...}
>
> swab32p(src) -> 0x72ef30a3 -> 01110010 11101111 00110000 10100011
>
>
> during loop #1 (s=31, shift=0):
>
> color = 0x72ef30a3 & (1<<31) ? 1 : 0; color is 0
> val |= 0 << 0; val is 0
>
> during loop #2 (s=30, shift=1):
>
> color = 0x72ef30a3 & (1<<30) ? 1 : 0; color is 1
> val |= 1 << 1; val is 2
>
> during loop #3 (s=29, shift=2):
>
> color = 0x72ef30a3 & (1<<29) ? 1 : 0; color is 1
> val |= 1 << 2; val is 6
>
> during loop #4 (s=28, shift=3):
>
> color = 0x72ef30a3 & (1<<28) ? 1 : 0; color is 1
> val |= 1 << 3; val is 0xe
>
> during loop #5 (s=27, shift=4):
>
> color = 0x72ef30a3 & (1<<27) ? 1 : 0; color is 0
> val |= 0 << 4; val is 0xe
>
> during loop #6 (s=26, shift=5):
>
> color = 0x72ef30a3 & (1<<26) ? 1 : 0; color is 0
> val |= 0 << 5; val is 0xe
>
> during loop #7 (s=25, shift=6):
>
> color = 0x72ef30a3 & (1<<25) ? 1 : 0; color is 1
> val |= 1 << 6; val is 0x4e
>
> during loop #8 (s=24, shift=7):
>
> color = 0x72ef30a3 & (1<<24) ? 1 : 0; color is 0
> val |= 0 << 7; val is 0x4e
>
> and so on...
>
> Finally val -> 11000101 00001100 11110111 01001110 -> 0xc50cf74e
>
> and FB_WRITEL(val, dst++) will write { 0x4e, 0xf7, 0x0c, 0xc5} into
> the frame buffer.
>
> Am I seeing it wrong ?
>
> > BTW what is your visual?
> >
>
> FYI, I give you all screen info, maybe something is miss-initialized...
>
> static struct fb_fix_screeninfo t6963c_fb_fix __initdata = {
> .id = DRIVER_NAME,
> .type = FB_TYPE_PACKED_PIXELS,
> .visual = FB_VISUAL_MONO01,
> .accel = FB_ACCEL_NONE,
> };
>
> static struct fb_var_screeninfo t6963c_fb_var __initdata = {
> .bits_per_pixel = 1,
> .red = {0, 1, 0},
> .green = {0, 1, 0},
> .blue = {0, 1, 0},
> .transp = {0, 0, 0},
> .activate = FB_ACTIVATE_NOW,
> .height = -1, /* height of picture in mm */
> .width = -1, /* width of picture in mm */
> .accel_flags = 0,
> .vmode = FB_VMODE_NONINTERLACED,
> };
>
> Franck
> -
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