Re: drivers/gpu/drm/radeon/radeon_test.c:45: undefined reference to `__udivdi3'

[Mr. James W. Laferriere]

	Hello Dave ,

On Sat, 19 Dec 2009, Dave Hylands wrote:
> Hi Jim,
> On Fri, Dec 18, 2009 at 12:54 PM, Mr. James W. Laferriere
> <babydr@xxxxxxxxxxxxxxxx> wrote:
> >        Hello Benjamin ,  I am not having a good time compiling 2.6.32.1 .
> > First RCU 'inline' difficulties then fusion-mpt 'inline' difficulty ,  Now
> > this .
> >        This one is not a simple as removing 'inline' from a statement .
> >        Would you please look into this ?  Anything else you need please just
> > ask .
> >        Please cc: me as I am not subscribed to linux-fbdev .
> >
> >                Tia ,  JimL
> ...snip...
> > drivers/built-in.o(.text+0x11345a): In function `radeon_test_moves':
> > drivers/gpu/drm/radeon/radeon_test.c:45: undefined reference to `__udivdi3'
> > make: *** [.tmp_vmlinux1] Error 1
>
> __udivdi3 is a gcc helper function used to do 64-bit division. This
> form of 64-bit division is not supported from within the kernel (which
> is why you get the undefined symbol).
>
> There is <asm/div64.h> which contains a macro called do_div which can
> perform a 64-bit dvision by a 32-bit divisor.
	Thank you ,  For replying .  Now I being a kernel level nothing ,  How 
does this help me get past the 'ld' time undefined reference ?  So we can have 
a kernel build complete (hopefully) successfully .

	I've another ? as well how is it that the drm/radeon_test.c is using 
(well at least referencing) a non-kernel symbol ?  That alone is rather 
interesting .

	But all I had to do is Disable DRM in the kernel .  Since this system is 
a remote device without a real need for DRI/DRM support that should cure my 
problem .  But someone else is going to need that support & I am sure they'll 
hit that same bug .

		Tia ,  JimL
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