Hello Michael, On Mon, Jun 04, 2018 at 09:27:40PM +1000, Michael Ellerman wrote: > "Gautham R. Shenoy" <e...@linux.vnet.ibm.com> writes: > > > From: "Gautham R. Shenoy" <e...@linux.vnet.ibm.com> > > > > The commit 78eaa10f027c ("cpuidle: powernv/pseries: Auto-promotion of > > snooze to deeper idle state") introduced a timeout for the snooze idle > > state so that it could be eventually be promoted to a deeper idle > > state. The snooze timeout value is static and set to the target > > residency of the next idle state, which would train the cpuidle > > governor to pick the next idle state eventually. > > > > The unfortunate side-effect of this is that if the next idle state(s) > > is disabled, the CPU will forever remain in snooze, despite the fact > > that the system is completely idle, and other deeper idle states are > > available. > > That sounds like a bug, I'll add? >
Yes, this is a bug-fix for a customer scenario which we encountered recently. > Fixes: 78eaa10f027c ("cpuidle: powernv/pseries: Auto-promotion of snooze to > deeper idle state") > Cc: sta...@vger.kernel.org # v4.2+ This patch applies cleanly from v4.13 onwards. Prior to that there are some (minor) conflicts. Should I spin a version separately for the prior stable versions ? > > cheers >