[arch-general] Nvidia Driver woes on Macbook 3,2

[Rodrigo Rivas]

On Fri, Dec 21, 2012 at 12:07 AM, LANGLOIS Olivier PIS -EXT <
olivier.pis.langlois at transport.alstom.com> wrote:

> >
> > Daniel Bryan:
> >
> > > Here's what I've tried in EFI mode:
> > >
> > > - standard nouveau setup - X sort of starts up but there are weird
> > >   artifacts, mouse doesn't work, and it freezes up pretty quickly.
> >
> > I had the same problem and found the following solution:
> >
> > - Install xf86-video-fbdev
> >
> This is very interesting. I was confronted with a similar problem with an
> old Nvidia card. I had weird visual artifacts with Nouveau and my card
> support has been dropped by the latest Nvidia driver. Their latest driver
> that supported it required Linux 2.6
>
> I ended up installing xf86-video-vesa as suggested in the Beginner's
> installation guide. It works well except for a reduction of the maximum
> resolution to what was available prior to switching to Arch. (this Pc is
> coming from Linux 2.6 Ubuntu system)
>
> I could not find much info about xf86-video drivers by finding such pages
> like:
>
> http://cgit.freedesktop.org/xorg/driver/xf86-video-fbdev/
>
> What is the difference between fbdev and vesa x driver? If my system is
> booting fine with the fb video driver for the vconsole, should I be better
> with the X fbdev video driver?
>

The fbdev video driver uses the linux framebuffer that is exposed by the
kernel driver to draw the X surfaces. Basically, the kernel driver (nouveau
or whatever) exposes the video memory as a big chunk of linear memory: you
write to that memoy, you get a pixel on the screen. Easy but slow, AFAIK no
acceleration at all. Everything is `memcpy()` and such.

The vesa driver uses the VESA extensions to talk directly to the graphic
card. That is an old interface that intended to standardize access to
different graphic cards back in the 16-bit era, and as such the nouveau or
whatever driver is not needed). Some modern graphic card still implement
it. Some 2D acceleration may be available, but I don't know if it is
actually used.

HTH
--
Rodrigo.