Bug#815986: nvidia-kernel-dkms:amd64: does not build for x86_64 kernel on i386 userspace

[Andreas Beckmann]

On 2016-02-26 14:40, Tomas Janousek wrote:
> Hi,
> 
> On Fri, Feb 26, 2016 at 01:59:07PM +0100, Andreas Beckmann wrote:
>> The make.log from -3 (or -4 which I uploaded this morning) would be
>> nice. It should contain the invocation of conftest.sh, which gets passed
>> all the flags it will use later on.
> 
> Okay, I'm attaching it. I think that the easiest solution would be to patch
> conftest.sh:build_cflags to add -m64 if the arch is x86_64. The kernel build
> does this in arch/x86/Makefile regardless of whether gcc defaults to 32/64, so
> conftest could do that too.

In 355.11 the problem comes from Kbuild:
NV_CONFTEST_CFLAGS := $(shell $(NV_CONFTEST_CMD) build_cflags)

conftest.sh should not derive compile flags on its own, instead the
KBUILD_CFLAGS from Kbuild should be used (which contains the -m64).
Once we understood hwo this works in the new build system (355+), we can
backport it to the older releases.
There is also LINUXINCLUDE which could provide us with all the -I flags ...

I tried a patch (in svn, but disabled) that adds KBUILD_CFLAGS to
NV_CONFTEST_CFLAGS, but that already makes the build fail. (I didn't
even think about testing 32/64 bit mixtures).


Andreas

PS: I just uploaded 355.11-3 to experimental, but primarily to get the
new packages through NEW.