On Mon, Sep 24, 2018 at 12:42:59PM +0300, Mika Westerberg wrote: > HP 6730b laptop has an ethernet NIC connected to one of the PCIe root > ports. The root ports itself are native PCIe hotplug capable. Now, > during boot after PCI devices are scanned the BIOS triggers ACPI bus > check directly to the NIC: > > [ 0.942239] ACPI: \_SB_.PCI0.RP06.NIC_: Bus check in hotplug_event() > > It is not clear why it is sending bus check but regardless the ACPI > hotplug notify handler calls enable_slot() directly (instead of going > through acpiphp_check_bridge() as there is no bridge) which ends up > handling special case for non-hotplug bridges with native PCIe hotplug. > This results a crash of some kind but the reporter only sees black > screen so it is hard to figure out the exact spot and what actually > happens. Based on few fix proposals it was tracked to crash somewhere > inside pci_assign_unassigned_bridge_resources(). > > In any case we should not really be in that special branch at all > because the ACPI notify happened to a slot that is not a PCI bridge (it > is just a regular PCI device). > > Fix this so that we only go to that special branch if we are calling > enable_slot() for a bridge (e.g the ACPI notification was for the bridge). > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=201127 > Fixes: 84c8b58ed3ad ACPI / hotplug / PCI: Don't scan bridges managed by native hotplug > Reported-by: Peter Anemone <peter.anemone@xxxxxxxxx> > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> Applied with Rafael's reviewed-by to pci/hotplug for v4.20, thanks! > --- > Changes from v1: > > * Pass bool instead of a bridge pointer > > drivers/pci/hotplug/acpiphp_glue.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c > index ef0b1b6ba86f..12afa7fdf77e 100644 > --- a/drivers/pci/hotplug/acpiphp_glue.c > +++ b/drivers/pci/hotplug/acpiphp_glue.c > @@ -457,17 +457,18 @@ static void acpiphp_native_scan_bridge(struct pci_dev *bridge) > /** > * enable_slot - enable, configure a slot > * @slot: slot to be enabled > + * @bridge: true if enable is for the whole bridge (not a single slot) > * > * This function should be called per *physical slot*, > * not per each slot object in ACPI namespace. > */ > -static void enable_slot(struct acpiphp_slot *slot) > +static void enable_slot(struct acpiphp_slot *slot, bool bridge) > { > struct pci_dev *dev; > struct pci_bus *bus = slot->bus; > struct acpiphp_func *func; > > - if (bus->self && hotplug_is_native(bus->self)) { > + if (bridge && bus->self && hotplug_is_native(bus->self)) { > /* > * If native hotplug is used, it will take care of hotplug > * slot management and resource allocation for hotplug > @@ -701,7 +702,7 @@ static void acpiphp_check_bridge(struct acpiphp_bridge *bridge) > trim_stale_devices(dev); > > /* configure all functions */ > - enable_slot(slot); > + enable_slot(slot, true); > } else { > disable_slot(slot); > } > @@ -785,7 +786,7 @@ static void hotplug_event(u32 type, struct acpiphp_context *context) > if (bridge) > acpiphp_check_bridge(bridge); > else if (!(slot->flags & SLOT_IS_GOING_AWAY)) > - enable_slot(slot); > + enable_slot(slot, false); > > break; > > @@ -973,7 +974,7 @@ int acpiphp_enable_slot(struct acpiphp_slot *slot) > > /* configure all functions */ > if (!(slot->flags & SLOT_ENABLED)) > - enable_slot(slot); > + enable_slot(slot, false); > > pci_unlock_rescan_remove(); > return 0; > -- > 2.18.0 >
