nv question...

[Alex Stewart]

On Wed, Feb 28, 2007 at 02:23:25AM -0500, Gene Heskett wrote:
> Thanks.  I knew it was 2d, or was when I last had an nvidia card, but 
> since I build my own kernels, ISTR I was building the nv driver as part 
> of the kernel tree, back at about the time RH switched from XFree86 to 
> the Xorg version over licensing squabbles.

I think you're recalling wrong.  As far as I know the nv driver has never been
related to the Linux kernel at all.  It's always been part of the XFree86/Xorg
package and not needed any kernel drivers or kernel configuration to work.

> Now, someone mentioned that the dkms utility would build the nvidia driver 
> fresh, for the kernel that was being booted if it hadn't already been 
> built for the current kernel.  Is this true?  I have it installed but no 
> idea if its properly configured to do that.

This sounds like you may be talking about the Nvidia (proprietary) driver,
which is not the same thing as the nv (Xorg) driver.  The Xorg nv driver is
2D-only, but will work with pretty much any kernel and does not need any
special kernel modules or configuration to work at all.  You do not need any
special utility to customize it for a particular kernel because it doesn't care
what kernel you're running.  (As far as I know, it ships by default as part of
the Xorg package for pretty much every distribution, so you probably already
have it built and ready to go, you just need to set it as your driver in your X
config file and restart X and it should Just Work(TM).  No kernel hacking
required.)

The proprietary Nvidia driver, on the other hand, offers 3D support, and
because of that it needs access to some bits of hardware that can't be accessed
without kernel-level drivers, so when you download the proprietary driver from
Nvidia's site, it comes with a kernel module that can be built to match
whatever Linux kernel you're using.

I have no idea about DKMS as I've never used it.  I believe it's intended to
make things like the Nvidia proprietary driver work more seamlessly when
changing kernels, but can't speak as to whether it actually works or not for
that purpose.  My personal suggestion, though, would be to try just using the
installer and instructions that Nvidia provides first and not use DKMS.  No
need to complicate things by adding a third-party utility until you know the
basic stuff works first.

(After you get it working in the usual way, then you might want to look into
DKMS to make it easier when you change kernels later, but DKMS shouldn't be
needed to get it to work initially..)

> In the instant case, this would be 2.6.20-ck1, but could be 2.6.21-rc2 by 
> the time I stuff this card into the slot the ati is occupying now, later 
> tomorrow I think.  I've just rebuilt this kernel with everything nvidia I 
> could spot as modules, so hopefully the transition will be relatively 
> painless.  Hopefully as simple as replacing the card, booting to runlevel 
> 3 which I do anyway, and running system-config-display.  But, I'm a 
> personal friend (or enemy depending on ones point of view) of that Murphy 
> that wrote all those laws, so who knows.

I've generally found Nvidia card support to be pretty painless, except for the
one (6800GS) card I've got right now, which seems to be the only one out there
that the nv driver just won't work with at all (but the proprietary driver
works fine).  Other than that, though, using the nv driver has always been
utterly painless (just set the right driver in your xorg.conf and it works).
The proprietary driver is a little more complicated, but if you follow the
instructions usually isn't a big deal either.

-alex