On Sun, Sep 02, 2018 at 04:27:14PM +0200, Lukas Wunner wrote: > On Fri, Aug 31, 2018 at 03:26:37PM -0600, Keith Busch wrote: > > This patch adds a channel state to a subordinate bus. When a DPC event is > > triggered, the DPC driver will set the channel state to frozen, and the > > pciehp driver will ignore link events if the subordinate bus is being > > managed by DPC error handling. > > > > This is safe because the pciehp and DPC drivers share the same > > interrupt. The DPC driver sets the bus state in the top-half interrupt > > context, and the pciehp driver checks and masks off link events in its > > bottom-half error handler. > > I really liked Sinan's approach of checking in pciehp whether a fatal > error is pending and waiting for it to be handled: > https://patchwork.ozlabs.org/patch/959464/ > > This seemed to avoid any races with DPC and is small and simple. > Can we pursue a solution along those lines? That introduces a completely different race between the error handling and hotplug threads. We don't control which interrupt fires first or any way ensure they're even the same event.
