On Tuesday, March 11, 2014 01:55:23 PM Dirk Brandewie wrote: > On 03/11/2014 01:57 PM, Rafael J. Wysocki wrote: > > On Tuesday, March 11, 2014 09:52:42 PM Rafael J. Wysocki wrote: > >> On Tuesday, March 11, 2014 01:17:20 PM Dirk Brandewie wrote: > >>> On 03/11/2014 01:20 PM, Rafael J. Wysocki wrote: > >>>> On Tuesday, March 11, 2014 10:58:59 AM Dirk Brandewie wrote: > >>>>> Hi Patrick, > >>>>> > >>>>> Sorry for the slow response you caught me taking a few days off :-) > >>>>> > >>>>> On 03/07/2014 07:49 AM, Patrik Lundquist wrote: > >>>>>> Hi, > >>>>>> > >>>>>> booting 3.13.5 on a dual socket Ivy Bridge-EP resulted in this error: > >>>>>> > >>>>>> [ 0.194139] smpboot: CPU0: Intel(R) Xeon(R) CPU E5-2687W v2 @ > >>>>>> 3.40GHz (fam: 06, model: 3e, stepping: 04) > >>>>>> ... > >>>>>> [ 0.246755] x86: Booting SMP configuration: > >>>>>> [ 0.250935] .... node #0, CPUs: #1 #2 #3 #4 #5 #6 #7 > >>>>>> [ 0.357648] .... node #1, CPUs: #8 #9 #10 #11 #12 #13 #14 #15 > >>>>>> [ 0.553293] x86: Booted up 2 nodes, 16 CPUs > >>>>>> [ 0.557666] smpboot: Total of 16 processors activated (108850.19 BogoMIPS) > >>>>>> ... > >>>>>> [ 5.210204] Intel P-state driver initializing. > >>>>>> [ 5.232407] Intel pstate controlling: cpu 0 > >>>>>> [ 5.253628] Intel pstate controlling: cpu 1 > >>>>>> [ 5.274899] cpufreq: __cpufreq_add_dev: ->get() failed > >>>>>> [ 5.294856] Intel pstate controlling: cpu 2 > >>>>>> [ 5.313553] Intel pstate controlling: cpu 3 > >>>>>> [ 5.332526] Intel pstate controlling: cpu 4 > >>>>>> [ 5.352347] Intel pstate controlling: cpu 5 > >>>>>> [ 5.372112] Intel pstate controlling: cpu 6 > >>>>>> [ 5.391097] Intel pstate controlling: cpu 7 > >>>>>> [ 5.410272] Intel pstate controlling: cpu 8 > >>>>>> [ 5.429092] Intel pstate controlling: cpu 9 > >>>>>> [ 5.447714] Intel pstate controlling: cpu 10 > >>>>>> [ 5.465872] Intel pstate controlling: cpu 11 > >>>>>> [ 5.482942] Intel pstate controlling: cpu 12 > >>>>>> [ 5.498414] Intel pstate controlling: cpu 13 > >>>>>> [ 5.513586] Intel pstate controlling: cpu 14 > >>>>>> [ 5.529200] Intel pstate controlling: cpu 15 > >>>>>> > >>>>>> CPU 1 is alive and well but missing the cpufreq driver. The system is > >>>>>> running fine otherwise. > >>>>> > >>>>> This is a regression introduced by commit > >>>>> da60ce9f2fa cpufreq: call cpufreq_driver->get() after calling ->init() > >>>> > >>>> So the problem is that ->get() may return 0 in intel_pstate and that causes > >>>> the core's _add function to abort? That would mean sample->freq equal to 0, > >>>> which shouldn't happen after intel_pstate_sample() called by intel_pstate_init_cpu(). > >>>> > >>>> Or am I missing anything? > >>>> > >>> > >>> The problem is that the core has been running less than 1% of the time based on > >>> the absolute values of aperf/mperf and the second sample has not been taken to > >>> get a more precise delta. > >>> > >>> I thought about running sample twice during init but didn't want to propose it > >>> until I made sure I was not going to break anything else. > >> > >> Well, ->setpolicy drivers are a special case anyway, so we can simply skip the > >> current frequency updates in __cpufreq_add_dev() and cpufreq_update_policy() > >> for them. > > > > In other words, we can do something like in the patch below I suppose? > > > > Rafael > > > > > > --- > > drivers/cpufreq/cpufreq.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > Index: linux-pm/drivers/cpufreq/cpufreq.c > > =================================================================== > > --- linux-pm.orig/drivers/cpufreq/cpufreq.c > > +++ linux-pm/drivers/cpufreq/cpufreq.c > > @@ -1137,7 +1137,7 @@ static int __cpufreq_add_dev(struct devi > > per_cpu(cpufreq_cpu_data, j) = policy; > > write_unlock_irqrestore(&cpufreq_driver_lock, flags); > > > > - if (cpufreq_driver->get) { > > + if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { > > policy->cur = cpufreq_driver->get(policy->cpu); > > if (!policy->cur) { > > pr_err("%s: ->get() failed\n", __func__); > > @@ -2150,7 +2150,7 @@ int cpufreq_update_policy(unsigned int c > > * BIOS might change freq behind our back > > * -> ask driver for current freq and notify governors about a change > > */ > > - if (cpufreq_driver->get) { > > + if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { > > new_policy.cur = cpufreq_driver->get(cpu); > > if (WARN_ON(!new_policy.cur)) { > > ret = -EIO; > > > or use has_target() Yes. Modified patch is appended. Patrik, can you please check if it helps? --- drivers/cpufreq/cpufreq.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) Index: linux-pm/drivers/cpufreq/cpufreq.c =================================================================== --- linux-pm.orig/drivers/cpufreq/cpufreq.c +++ linux-pm/drivers/cpufreq/cpufreq.c @@ -1137,7 +1137,7 @@ static int __cpufreq_add_dev(struct devi per_cpu(cpufreq_cpu_data, j) = policy; write_unlock_irqrestore(&cpufreq_driver_lock, flags); - if (cpufreq_driver->get) { + if (cpufreq_driver->get && has_target()) { policy->cur = cpufreq_driver->get(policy->cpu); if (!policy->cur) { pr_err("%s: ->get() failed\n", __func__); @@ -2150,7 +2150,7 @@ int cpufreq_update_policy(unsigned int c * BIOS might change freq behind our back * -> ask driver for current freq and notify governors about a change */ - if (cpufreq_driver->get) { + if (cpufreq_driver->get && has_target()) { new_policy.cur = cpufreq_driver->get(cpu); if (WARN_ON(!new_policy.cur)) { ret = -EIO; -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html