[2.4.20] e1000 as module gives unresolved symbol _mmx_memcpy

[2.4.20] e1000 as module gives unresolved symbol _mmx_memcpy

[Jurgen Kramer]

Hi,

While trying to use the e1000 as a module with kernel 2.4.20 it gives
me a unresolved symbol while trying to insmod the module. The offending
symbol is _mmx_memcpy. When the driver is compiled into the kernel
there's no problem.

I am running the kernel on a VIA Eden with 800MHz C3. Does this have
something to do with the fact that kernels for the VIA C3 are now
compiled with i486 optimisations (so maybe no MMX support?)?

Cheers,

Jurgen

Re: [2.4.20] e1000 as module gives unresolved symbol _mmx_memcpy

[Jurgen Kramer]

Thanks, I was thinking along the same lines after
discovering that a lot of other modules had the same problem...:-)
After a mrproper everything is working OK now.

But just to get a complete picture, does it mean that

a) a kernel build for a VIA C3 doesn't use MMX, userspace programs can
still use it

or

b) Both kernel and userspace can't use MMX any more

If option b) would be true a lot of people who are using the VIA Eden
platform to view Divx and other multimedia material will be probably be
hurt performance wise. If the MMX implementation on the C3 is any good.

Greetings,

Jurgen

Re: [2.4.20] e1000 as module gives unresolved symbol _mmx_memcpy

[Alan Cox]

On Fri, 2003-01-10 at 13:45, Jurgen Kramer wrote:
> Hi,
> 
> While trying to use the e1000 as a module with kernel 2.4.20 it gives
> me a unresolved symbol while trying to insmod the module. The offending
> symbol is _mmx_memcpy. When the driver is compiled into the kernel
> there's no problem.
> 
> I am running the kernel on a VIA Eden with 800MHz C3. Does this have
> something to do with the fact that kernels for the VIA C3 are now
> compiled with i486 optimisations (so maybe no MMX support?)?

Make sure you build from distclean if you've built for other cpu options
before. (cp .config ..; make distclean; cp ../.config .config; make oldconfig..

Re: [2.4.20] e1000 as module gives unresolved symbol _mmx_memcpy

[Alan Cox]

On Fri, 2003-01-10 at 15:10, Jurgen Kramer wrote:
> a) a kernel build for a VIA C3 doesn't use MMX, userspace programs can
> still use it

Basically true. It might be instructive to do more benching on this with
the C3 and MMX especially if the new cores add full prefetch stuff

> b) Both kernel and userspace can't use MMX any more

MMX is designed to need no OS support. SSE/SSE2 do need OS helpers but
not MMX.