Re: vfb.c (ruby)

[James S. <jsi...@ac...>]

> > >     length = (xres_virtual+bpp-1)/bpp;
> It is obviously wrong... For xres = 640 at 16bpp you should get
> 1280 bytes and for 8bpp 640 bytes...

Dah!! I don't know what I was thinking. I was just trying to figure what
the orginal code was doing. Which I stil can't figure it out yet. Petr do
you have a idea what Geert was thinking when he wrote that routine? 


> > Length is the value that placed in fb_fix-screeninfo line_length which is
> > the number of bytes wide the way th card sees a scanline. Take a voodoo
> > card for example. No matter what mode you set the card in line_length is
> > 1024. So take for example 800x600. We have video memory layed out like
> > this:
> Then easiest thing is that driver will always report xres_virtual = 1024.
> Or it can compute line_length as it wants, but for such hardware then 
> get_line_length() should not depend on xres_virtual.

Right, you wouldn't need a get_line_length routine. 


Q: Why did they deprecate a.out support in linux?
A: Because a nasty coff is bad for your elf.

James Simmons  [jsi...@li...]               ____/| 
fbdev/console/gfx developer                             \ o.O| 
http://www.linux-fbdev.org                               =(_)= 
http://linuxgfx.sourceforge.net                            U
http://linuxconsole.sourceforge.net