Hi Mulyadi/Spiro, Can you please help me in partially enabling/disabling optimizations, because I was consistently hitting at the below problem when building the kernel after disabling the optimization ERROR: "intel_gmbus_is_forced_bit" [drivers/gpu/drm/i915/i915.ko] undefined! ERROR: "__udivdi3" [drivers/gpu/drm/i915/i915.ko] undefined! make[2]: *** [__modpost] Error 1 make[1]: *** [modules] Error 2 make: *** [sub-make] Error 2 Can I enable optimization for this i915 driver, so that I can contine with my kernel building ? Thanks, Prabhu On Tue, Jun 28, 2011 at 7:21 AM, Mulyadi Santosa <mulyadi.santosa@gmail.com>wrote:
Hi Spiro
On Tue, Jun 28, 2011 at 01:40, Spiro Trikaliotis <ml-kernelnewbies@spiro.trikaliotis.net> wrote:
On the other hand: With optimisations disabled, the kernel behaves differently than it would with optimisations. That's why many people prefer to keep them switched on, and only disable them partially if really, really needed.
I agree...even I still have mixed conclusion whether to go or no go with -O when dealing with -O and debugging. I guess one of the biggest offenders are: inlining, dead code (and symbols) elimination, substitution with specific machine specific opcode (not really sure, is -march has relationship with -O)...
-- regards,
Mulyadi Santosa Freelance Linux trainer and consultant
blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
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