On Thu, Aug 08, 2019 at 10:32:38PM +0200, Thomas Gleixner wrote: > Valdis, > > On Thu, 8 Aug 2019, Valdis Klētnieks wrote: > > On Thu, 08 Aug 2019 22:04:03 +0200, Thomas Gleixner said: It isn't > > clear that whatever is doing the device_initcall()s will be able to > > do any reasonable recovery if we return an error, so any error > > recovery is going to have to happen before the function returns. It > > might make sense to do an 'if (ret) return;' before going further in > > the function, but given the comment a few lines further down about > > ignoring errors, it was apparently considered more important to > > struggle through and register stuff in sysfs even if umwait was > > broken.... > > I missed that when going through it. > > The right thing to do is to have a cpu_offline callback which clears > the umwait MSR. That covers also the failure in the cpu hotplug setup. > Then handling an error return makes sense and keeps everything in a > workable shape.
When cpu is offline, the MSR won't be used. We don't need to clear it, right? Thanks. -Fenghua
