On Tue, Jul 10, 2012 at 04:56:15PM -0600, Bjorn Helgaas wrote: > On Sat, Jun 23, 2012 at 1:42 AM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote: > > If surprise removal is not supported, that event get dropped later. > > So there is no point to enable that. > > > > Also some sick chipset have those bit flip around when the card is not present. > > and make log full of useless warning. > > HP_SUPR_RM tests the Slot Capabilities "Hot-Plug Surprise" bit, which > indicates that an adapter might be *removed* without prior > notification (sec 7.8.9). > > PCI_EXP_SLTCTL_PDCE is the Slot Control "Presence Detect Changed > Enable" bit, which enables interrupts for any change in the Slot > Status "Presence Detect State", i.e., we may get interrupts for either > add or remove events. > > In interrupt_event_handler(), we drop both add and remove events if > !HP_SUPR_RM(). Specifically, we drop *add* events if surprise > *removal* isn't supported. That seems strange -- just from reading > the spec, it seems that a surprise *add* could occur even if the > "Hot-Plug Surprise" bit is not set. > > So I'm not convinced that we should even bother looking at the > "Hot-Plug Surprise" bit... Maybe we'd be better off if we just > removed that HP_SUPR_RM() test in interrupt_event_handler() and always > called handle_surprise_event(). What bad things would happen if we did the following? I have no way to test this, but I don't understand what benefit there is in testing HP_SUPR_RM() here. diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c index 27f4429..4bbe257 100644 --- a/drivers/pci/hotplug/pciehp_ctrl.c +++ b/drivers/pci/hotplug/pciehp_ctrl.c @@ -463,9 +463,8 @@ static void interrupt_event_handler(struct work_struct *work) break; case INT_PRESENCE_ON: case INT_PRESENCE_OFF: - if (!HP_SUPR_RM(ctrl)) - break; - ctrl_dbg(ctrl, "Surprise Removal\n"); + ctrl_dbg(ctrl, "Presence Detect changed (now %spresent)\n", + info->event_type == INT_PRESENCE_OFF ? "not " : ""); handle_surprise_event(p_slot); break; default: -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
