On 11/29/2011 02:09 AM, Benjamin Herrenschmidt wrote: > On Mon, 2011-11-28 at 16:33 +0530, Deepthi Dharwar wrote: > >> On an LPAR if cpuidle is disabled, ppc_md.power_save is still set to >> cpuidle_idle_call by default here. This would result in calling of >> cpuidle_idle_call repeatedly, only for the call to return -ENODEV. The >> default idle is never executed. >> This would be a major design flaw. No fallback idle routine. >> >> We propose to fix this by checking the return value of >> ppc_md.power_save() call from void to int. >> Right now return value is void, but if we change this to int, this >> would solve two problems. One being removing the cast to a function >> pointer in the prev patch and this design flaw stated above. >> >> So by checking the return value of ppc_md.power_save(), we can invoke >> the default idle on failure. But my only concern is about the effects of >> changing the ppc_md.power_save() to return int on other powerpc >> architectures. Would it be a good idea to change the return type to int >> which would help us flag an error and fallback to default idle? > > I would have preferred an approach where the cpuidle module sets > ppc_md.power_save when loaded and restores it when unloaded ... but that > would have to go into the cpuidle core as a powerpc specific tweak and > might not be generally well received. > > So go for it, add the return value, but you'll have to update all the > idle functions (grep for power_save in arch/powerpc to find them). > Thanks Ben. Yes, I will update all the idle functions under powerpc. I will re-work these patches with the discussed changes. Regards, Deepthi _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/linux-pm
