On Wednesday, April 01, 2015 08:04:34 PM Thomas Schlichter wrote: > Hello, Hi, > I do have a Samsung NC20 netbook which provides the C-states C1 and C2 to the > OS when connected to AC, and additionally provides the C3 C-state when > disconnected from AC. With the current kernels I have these two problems > (regressions): > > 1. The number of C-states shown in sysfs is fixed to the number of C-states > present at boot. > If I boot with AC connected, I always only see the C-states up to C2 even > if I disconnect AC. > > The reason is commit 130a5f692425e6237229598a8624da0a247f33d5 > "ACPI / cpuidle: remove dev->state_count setting". It removes the update of > dev->state_count, but sysfs uses exactly this variable to show the > C-states. > > The fix is to use drv->state_count in sysfs. As this is currently the last > user of dev->state_count, this variable can be completely removed. And this > is exactly what Bartlomiej Zolnierkiewicz's not yet applied patch "[PATCH > v2 9/9] cpuidle: remove state_count field from struct cpuidle_device" > http://marc.info/?m=138756533317836 does. > > Long story short: That patch fixes problem 1 for me. Rafael, please apply that patch (as Thomas has noticed it is required to fix issue with dynamic dev/drv->state_count updates, sorry for not catching it earlier). [ Originally the whole series was dropped when patch #8 ("[PATCH v2 8/9] intel_idle: use the common cpuidle_[un]register() routines") turned out to introduce some problems. Patches #1-7 were later re-merged but not patch #9 (which is independent of patch #8). ] > 2. After a AC->DC or DC->AC transition, the name and description of the > POLLING C-state become "<null>". > > Here, the reason is commit d7c7f103262bc2248548ed0e113e916e843c4eeb > "cpuidle: don't call poll_idle_init() for every cpu". It only calls > poll_idle_init() during cpuidle_register_driver() instead of > cpuidle_enable_device() and thus does not re-initialize the fields of > drv->states[0] after acpi_processor_setup_cpuidle_states() cleared them. > > Here, the fix is to _not_ clear drv->states[0] in > acpi_processor_setup_cpuidle_states(). For this purpose I created a small > patch. This patch looks fine to me. FWIW: Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx> > For your convenience, both of the fixing patches are attached to this mail. > The first one is necessary for all kernels since 3.14, the second one for all > kernels since 3.13. So I'd propose to push both of them also to the necessary > stable kernels. Sounds good to me. Thank you for working on this. Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
