On 04/03/2011 02:30 AM, Alan Cox wrote: >> This patch series was posted in reply to a table of contents >> >> https://lkml.org/lkml/2011/4/2/8 >> >> "By the end of this series, pm_idle is removed as a public >> x86 idle-loop registration mechanism. A few other things are >> cleaned up in the process." > > Ok so lets rewind a bit - why do we want to remove pm_idle rather than > just fix up the way registration occurs. It's just a symbol, one trivial > interface that is exported and perhaps wants the export method tidying up. > >> Trinabh also replied to you, pointing one of the previous >> LKML discussions about the mis-use of pm_idle. > > And there are misuses of just about every kernel symbol - kmalloc for > example causes some people a lot of trouble ! There are other problems too. This design of pm_idle has been copied by numerous other architectures. arm/blackfin/cris/ia64/m32r/m68knomm /microblaze/mn10300/sh/sparc all have pm_idle. This will keep spreading in future I guess. > >> We'll create a new APM cpuidle driver in Linux (Trinabh prototyped one), >> and at the same time, schedule it for removal in a year. Personally, >> I think it is make-work, and in real-life it is more likely to do >> more harm than removing apm_idle, but I don't want to stand in the >> way of process. > > So you could just leave it alone - that's less work, less disruption and > doesn't do any harm at all. > > As I read this the plan at the moment otherwise is > > - churn up all the code > - remove PM idle hook > - rewrite the APM code > - replace the APM code > > whereas you could just leave the symbol exported or even just a hook to > make people to do it right using: > > int register_pm_idle(function); A patch was posted to do exactly this; see https://lkml.org/lkml/2010/10/19/449 . The problem is that it results in two places of registration: cpuidle subsystem and this. It was pointed that 99.99% of people run cpuidle and we should directly call cpuidle and use its registration mechanism rather than duplicate code. Thanks, -Trinabh _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
