Re: [PATCH v3] PCI: pciehp: Fix the slot in BLINKINGON_STATE when Presence Detect Changed event occurred

[Lukas Wunner <lukas@wunner.de>]

On Fri, May 05, 2023 at 09:38:59AM +0800, Rongguang Wei wrote:
> On 4/29/23 10:30 PM, Lukas Wunner wrote:
> > On Fri, Apr 21, 2023 at 10:56:41AM +0800, Rongguang Wei wrote:
> > > --- a/drivers/pci/hotplug/pciehp_ctrl.c
> > > +++ b/drivers/pci/hotplug/pciehp_ctrl.c
> > > @@ -256,6 +256,7 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
> > >  	present = pciehp_card_present(ctrl);
> > >  	link_active = pciehp_check_link_active(ctrl);
> > >  	if (present <= 0 && link_active <= 0) {
> > > +		ctrl->state = OFF_STATE;
> > >  		mutex_unlock(&ctrl->state_lock);
> > >  		return;
> > >  	}
> > 
> > It has occurred to me that we also need to turn off the Power Indicator,
> > lest it continues blinking after the 5 second interval.  Sorry for not
> > spotting this earlier.  And I'm thinking that making the state change
> > conditional on BLINKINGON_STATE would serve clarity.
> > 
> > So could you please amend the above as follows and verify it fixes the
> > issue for you?
> 
> It works fine.
> 
> >  	if (present <= 0 && link_active <= 0) {
> > +		if (ctrl->state == BLINKINGON_STATE) {
> 
> I have a little question and is there necessary to add
> "cancel_delayed_work(&ctrl->button_work);" here?

Right, that seems reasonable.  pciehp_queue_pushbutton_work() becomes
a no-op once the state has been changed to OFF_STATE, so there's no
real harm if the work item is left in the queue, but canceling it is
definitely cleaner.

And a message to the user might be helpful as well to indicate that
the button press hasn't resulted in slot bringup due to it being
empty.  So maybe something like the below?


diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index 529c34808440..32baba1b7f13 100644
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c
@@ -256,6 +256,14 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
 	present = pciehp_card_present(ctrl);
 	link_active = pciehp_check_link_active(ctrl);
 	if (present <= 0 && link_active <= 0) {
+		if (ctrl->state == BLINKINGON_STATE) {
+			ctrl->state = OFF_STATE;
+			cancel_delayed_work(&ctrl->button_work);
+			pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF,
+					      INDICATOR_NOOP);
+			ctrl_info(ctrl, "Slot(%s): Card not present\n",
+				  slot_name(ctrl));
+		}
 		mutex_unlock(&ctrl->state_lock);
 		return;
 	}