[PATCH 2/2] I/O port access routines

ext Luc Verhaegen libv at skynet.be
Thu Nov 19 08:20:41 PST 2009

On Thu, Nov 19, 2009 at 06:06:47PM +0200, Tiago Vignatti wrote:
> On Thu, Nov 19, 2009 at 01:45:57AM +0100, ext Luc Verhaegen wrote:
> > 
> > But the main point of this mail was ignored. Why did existing xorg pci 
> > infrastructure have to be reinvented like that instead of adding a new 
> > backend and fixing up the bad patches? Why did RAC get thrown away like 
> > that? Why does this NIH have to keep on repeating itself?
> > 
> The main reason is because we were needing a PCI resource broker for the
> entire system and not for one process only. And X was touching the PCI
> resources directly with RAC.. oops! We don't need and our 21st century's
> kernels do it pretty well for us :)
>             Tiago

You're talking RAC backend here. Once the RAC was initialised to know 
what resources this hardware needed, it handled everything for the 
driver without having to care for anything. This for memory, io and vga 
(a subclass of io).

What i see now is that _everything_ got reinvented, instead of having 
written up a backend for a modern operating system, and maybe adjusting 
initialisation on the driver level (as part of this info really can be 
retrieved from the os now).

Re-inventing everything is exactly the criticism that libpciaccess got, 
apart from it having not been tested on any worthwhile subset of 
hardware. Yet people still seem unable or unwilling to learn from their 

Luc Verhaegen.

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