Re: Mirrored and shiftet fonts and logos

[Michael Kaufmann <kaufmann@sohard.de>]

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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