How to make xorg prefer "nvidia" over "nv" driver in a xorg.conf less configuration?

[Francesco Pretto]

Daniel Stone <daniel <at> fooishbar.org> writes:
> If you want to configure Xorg, why not use xorg.conf?
> 

As I've just answered to Aaron, I was able to produce a xorg.conf that works for
my setup. I consider it a workaround (somewhat dirty) as it's based on failing
of another driver loading.

There would be 3 possible approaches to solve the solve the problem in a more
clean way:

- Priority mechanism -> putting "nvidia" at higher priority than "nv";
- Blacklists -> blacklisting "nv"
- HAL fdi policies -> select "nvidia" driver when a nvidia card is found.

Even if the linux kernel loader provide at least partial support for all the 3
methods, I agree the first 2 ones (priority and blacklists) are too much generic
to be really useful to many Xorg users. Moreover, they involve auditing the very
existence of other drivers than "nvidia", like "nv" or "vesa": what if for
example "nv" is already at the maximum priority and there's no way to prefer
"nvidia" over it unless lowering its priority? What if blacklisting "nv" and
"vesa" lead to unworking setups in many other useful use cases?

The third approach seems nice, something like:

<deviceinfo version="0.2">
  <device>
    <match key="system.hardware.primary_video.vendor" int="0x10de">
       <merge key="video.x11_driver" type="string">nvidia</merge>
    </match>
  </device>
</deviceinfo>

would be cool to have and for sure there's already much code in the Xserver to
begin with to add this support even for video devices and monitors
configurations, similarly to what happen for the input layer.