Re: Mirrored and shiftet fonts and logos

On Saturday 14 December 2002 18:53, André Stierenberg wrote:

i´m using the framebuffer driver pxafb for my board using the pxa processor
(Accelent IDP). I have a 4 bit monocrom display. when I run the framebuffer
I have some problems. The text in the console it in some way shifted. The
two parts of the font are switched. The first 4 pixels are at dest+2 and
the last 4 pixels at dest+0. And both parts are mirrored. Now I have done
the following in fbcon_cfb4.c in function fbcon_cfb4_putcs:

  for (rows = fontheight(p), dest = dest0; rows-- ; dest += bytes) {
      fb_writew((nibbletab_cfb4[rv(*cdat) >> 4] & eorx) ^ bgx, dest+2);
      fb_writew((nibbletab_cfb4[rv(*cdat++) & 0xf] & eorx) ^ bgx, dest+0);
  }


The function rv will reverse the bit order (bit 1 is bit 8, bit 2 is bit
7.. etc.).
And i have swaped the destination offset.
Now the characters are printed correctly. And in the linux logo, the
pinguin, something is also wrong. It seems the some pixels are mirrored too
whereas other pixels are correct.

What could this be and in what way can i fix the problem?

i had exactly the same problem, but i fixed it on the hardware side.
I changed the databus between the video controller and the LCD.
My display has a 4bit width databus, so i exchanged D0 with D3 and D1 with D2.
Now i have a clear picture (logo, font, ...).

Bye
Michael


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