Problems with disabling Optimization

Dave Hylands dhylands at
Thu Jun 2 10:49:40 EDT 2011

Hi Prabhu,

On Thu, Jun 2, 2011 at 3:28 AM, Prabhu nath <gprabhunath at> wrote:
> Dear All,
>                Disabling O2 and Os on Kernel building, I am getting the
> following error. Can you please help me in debugging this.
>        Saw some info on the net, but could not resolve it.
> ERROR: "intel_gmbus_is_forced_bit" [drivers/gpu/drm/i915/i915.ko] undefined!
> ERROR: "__udivdi3" [drivers/gpu/drm/i915/i915.ko] undefined!

This means that your code is trying to do some type of 64-bit
arithmetic (probably a divide) which isn't directly supported in the

There is a do_div macro/function from arch/arm/include/asm/div64.h, or

Dave Hylands
Shuswap, BC, Canada

More information about the Kernelnewbies mailing list