On Thu, Feb 16, 2017 at 10:12:47PM -0800, Yinghai Lu wrote: > On one system during power off slot, find card get power on right away. > # echo 0 > /sys/bus/pci/slots/1/power > pci_hotplug: power_write_file: power = 0 > pciehp 0000:16:00.0:pcie004: pciehp_get_power_status: SLOTCTRL a8 value read 11f1 > pciehp 0000:16:00.0:pcie004: pciehp_unconfigure_device: domain:bus:dev = 0000:17:00 > pci 0000:17:00.0: PME# disabled > pci 0000:17:00.0: freeing pci_dev info > pciehp 0000:16:00.0:pcie004: pending interrupts 0x0010 from Slot Status > pciehp 0000:16:00.0:pcie004: pciehp_power_off_slot: SLOTCTRL a8 write cmd 400 > pciehp 0000:16:00.0:pcie004: pending interrupts 0x0108 from Slot Status > pciehp 0000:16:00.0:pcie004: Slot(1): Link Down > pciehp 0000:16:00.0:pcie004: Slot(1): Link Down event ignored; already powering off > pciehp 0000:16:00.0:pcie004: pciehp_green_led_off: SLOTCTRL a8 write cmd 300 > pciehp 0000:16:00.0:pcie004: pending interrupts 0x0018 from Slot Status <====== > pciehp 0000:16:00.0:pcie004: Slot(1): Card present > pciehp 0000:16:00.0:pcie004: pciehp_get_power_status: SLOTCTRL a8 value read 17f1 > pciehp 0000:16:00.0:pcie004: pending interrupts 0x0010 from Slot Status > pciehp 0000:16:00.0:pcie004: pciehp_power_on_slot: SLOTCTRL a8 write cmd 0 > pciehp 0000:16:00.0:pcie004: pciehp_green_led_blink: SLOTCTRL a8 write cmd 200 > pciehp 0000:16:00.0:pcie004: pending interrupts 0x0010 from Slot Status > pciehp 0000:16:00.0:pcie004: pciehp_check_link_active: lnk_status = f103 > pciehp 0000:16:00.0:pcie004: pending interrupts 0x0108 from Slot Status > pciehp 0000:16:00.0:pcie004: Slot(1): Link Up > ... > > Somehow PDC bit get set, and during handling interrupt that is caused by > CC, that PDC also get handled, and the card get powered on again. > > In pcie_enable_notification(), we already only enable notification > for PDC when attention button is not there. > So we can safely add checking in pciehp_isr() to skip that PDC handling. > > Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx> > > --- > drivers/pci/hotplug/pciehp_hpc.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > Index: linux-2.6/drivers/pci/hotplug/pciehp_hpc.c > =================================================================== > --- linux-2.6.orig/drivers/pci/hotplug/pciehp_hpc.c > +++ linux-2.6/drivers/pci/hotplug/pciehp_hpc.c > @@ -618,8 +618,9 @@ static irqreturn_t pciehp_isr(int irq, v > present = !!(status & PCI_EXP_SLTSTA_PDS); > ctrl_info(ctrl, "Slot(%s): Card %spresent\n", slot_name(slot), > present ? "" : "not "); > - pciehp_queue_interrupt_event(slot, present ? INT_PRESENCE_ON : > - INT_PRESENCE_OFF); > + if (!ATTN_BUTTN(ctrl)) > + pciehp_queue_interrupt_event(slot, present ? > + INT_PRESENCE_ON : INT_PRESENCE_OFF); I don't think it really makes sense to tie PDC handling with the attention button. It might happen to avoid the problem on your system, but I don't see the logical connection between them. Can you reproduce this by disabling pciehp and driving this sequence manually with setpci? I suspect that we are tripping over our own feet because we read PCI_EXP_SLTSTA once, clear it (probably too early), then queue multiple events, then process those events possibly simultaneously. > } > > /* Check Power Fault Detected */
