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However, on all Intel hardware I looked at > closely, a 0->1 transition of the enable bit causes an immediate IRQ. > Hence disabling channels isn't a good idea there. Set a "long" timeout > instead. > > Along with that also "clear" the channel's "next event", for it to be > properly written by whatever the next user is going to want (possibly > avoiding too early an IRQ). > > Further, along the same lines, don't enable channels early when starting > up an IRQ. This doesn't need to happen earlier than from > set_channel_irq_affinity() (once a channel goes into use the very first > time). This eliminates a single instance of > > (XEN) [VT-D]INTR-REMAP: Request device [0000:00:1f.0] fault index 0 > (XEN) [VT-D]INTR-REMAP: reason 25 - Blocked a compatibility format interrupt request > > during boot. (Why exactly there's only one instance, when we use multiple > counters and hence multiple IRQs, I can't tell. My understanding would be > that this was due to __hpet_setup_msi_irq() being called only after > request_irq() [and hence the .startup handler], yet that should have > affected all channels.) > > Fixes: 3ba523ff957c ("CPUIDLE: enable MSI capable HPET for timer broadcast") > Signed-off-by: Jan Beulich > Release-Acked-by: Oleksii Kurochko Reviewed-by: Roger Pau Monné Thanks, Roger.