Am Dienstag, 7. August 2018, 10:54:06 CEST schrieb Marc Zyngier:
> Enabling the interrupt early, before power has been applied to the
> device, can result in an interrupt being delivered too early if:
>
> - the IOMMU shares an interrupt with a VOP
> - the VOP has a pending interrupt (after a kexec, for example)
>
> In these conditions, we end-up taking the interrupt without
> the IOMMU being ready to handle the interrupt (not powered on).
>
> Moving the interrupt request past the pm_runtime_enable() call
> makes sure we can at least access the IOMMU registers. Note that
> this is only a partial fix, and that the VOP interrupt will still
> be screaming until the VOP driver kicks in, which advocates for
> a more synchronized interrupt enabling/disabling approach.
>
> Fixes: 0f181d3cf7d98 ("iommu/rockchip: Add runtime PM support")
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Reviewed-by: Heiko Stuebner <heiko@xxxxxxxxx>
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