On Wed, 21 Jun 2023 at 08:21, Tushar Nimkar <quic_tnimkar@xxxxxxxxxxx> wrote: > > Many thanks again, > > On 6/16/2023 4:25 PM, Ulf Hansson wrote: > > On Wed, 14 Jun 2023 at 08:43, Tushar Nimkar <quic_tnimkar@xxxxxxxxxxx> wrote: > > > > > Right. I am not saying it's the perfect solution, but it seems like it > > could potentially solve the problem for many cases. > > > > If you want some help to turn the cpuidle-psci driver into a loadable > > module, just reach out, I am happy to help. > > > Thanks :) Np! > Making cpuidle-psci as loadable does not hold good for target does not > support DLKM, in addition to it rpmh driver has dependency on > cpuidle-psci for pm-domain and rpmh probe will get defer, their are > driver which depends on rpmh probe like interconnect, clk etc. And > eventually dependent driver probe defers which are essential for Linux > boot-up. > Hope you got scenario for getting probe defer if we make cpuidle-psci as > loadable. I understand your concern, but you have got my idea wrong. I was suggesting turning the cpuidle-psci driver into a loadable module - not the cpuidle-psci-domain driver. The latter is the genpd provider, which consumers like rpmh need to probe. > > I have below options as well > [A]: Can we think of making "governor/param_governor" > module_param_string, string named governor only to load. In that way > need to remove check [3]. Let's say string passed as "teo" then it will > not load "menu" and loads "teo" once comes-up. > > [B]: Can we think of making cpuidle.off as writable, let governors to > register (i.e remove check [4]) and allow cpuidle_init() to happen (i.e > remove check [5]) > So in this way cpuidle.off=1, your idle state can not be selected > because [6] and later we can write off=0 to let same check [6] to fail. > > [C]: Coming to this series approach...What is best way to utilize > already present Flag-CPUIDLE_FLAG_OFF ? > Since we can not add new DT property to take decision in driver as it's > not HW feature to be expose in device tree [7]. Can we introduce new > module_param() for making idle-state disable default and utilize > CPUIDLE_FLAG_OFF? maybe similar to [8] > > happy to hear your thoughts! In general I am not in favor of module parameters, but maybe it's the best option to solve this problem. We need Rafael's and Daniel's opinion to conclude. However, to me, I still think the easiest approach would be to turn the cpuidle-psci driver into a loadable module. Let me hack on that and post a few patches that you can test for this. > > > [3] > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/cpuidle/governor.c?h=next-20230620#n93 > > [4] > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/cpuidle/governor.c?h=next-20230620#n86 > > [5] > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/cpuidle/cpuidle.c?h=next-20230620#n808 > > [6] > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/kernel/sched/idle.c?h=next-20230620#n167 > > [7] > https://lore.kernel.org/lkml/20230608085544.16211-1-quic_tnimkar@xxxxxxxxxxx/T/#m5d6012b0dfcff700f48c0efbba629382f18ee33b > > [8] > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/idle/intel_idle.c?h=next-20230620#n2160 > > [...] > > Kind regards Uffe
