Re: [Linux-fbdev-devel] cfb_copyarea()

[Geert U. <ge...@li...>]

On Mon, 19 Aug 2002, Geert Uytterhoeven wrote:
> In cfb_copyarea(), `tmp' must be unsigned long because it is used to store
> unsigned long values (see patch at the end).
> 
> cfb_copyarea() also doesn't clear the bits to modify in the first and last
> words of a line, e.g. it does
> 
> |	last = (FB_READ(src) & start_mask);
> |
> |	if (shift > 0) 
> |		FB_WRITE(FB_READ(dst) | (last >> shift_right), dst);
>                          ^^^^^^^^^^^^
> After this read, the bits to modify must be cleared first, before the OR!
> 
> I'm working on a version of cfb_copyarea() that fixes this and handles _all_
> possible values of var.bits_per_pixel (the current code assumes
> var.bits_per_pixel is a multiple of 8). Stay tuned!
                        ^^^^^^^^^^^^^^^
Oops, actually 8, 16, or 32 only (and 24 after Antonino Daplas' patch). I also
plan on relaxing the current limitation that line_size must be a multiple of
sizeof(unsigned long).

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@li...

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds