On 11/12/19 3:59 PM, Stuart Hayes wrote: > The pciehp interrupt handler pciehp_isr() will read the slot status > register and then write back to it to clear just the bits that caused the > interrupt. If a different interrupt event bit gets set between the read and > the write, pciehp_isr() will exit without having cleared all of the > interrupt event bits, so we will never get another hotplug interrupt from > that device. > > That is expected behavior according to the PCI Express spec (v.5.0, section > 6.7.3.4, "Software Notification of Hot-Plug Events"). > > Because the "presence detect changed" and "data link layer state changed" > event bits are both getting set at nearly the same time when a device is > added or removed, this is more likely to happen than it might seem. The > issue can be reproduced rather easily by connecting and disconnecting an > NVMe device on at least one system model. > > This patch fixes the issue by modifying pciehp_isr() to loop back and > re-read the slot status register immediately after writing to it, until > it sees that all of the event status bits have been cleared. > > Signed-off-by: Stuart Hayes <stuart.w.hayes@xxxxxxxxx> Bjorn, Do you have any comments or issues with this patch set? Anything I can do? Thanks! Stuart
