On Mon, Nov 25, 2019 at 03:03:23PM -0600, Stuart Hayes wrote: > > 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? Were you planning to address Lukas' comments? https://lore.kernel.org/r/20191114025022.wz3gchr7w67fjtzn@xxxxxxxxx
