Hi,
On 4/16/23 11:18 PM, Lukas Wunner wrote:
> On Mon, Apr 03, 2023 at 01:46:19PM +0800, Rongguang Wei wrote:
>> When a Presence Detect Changed event has occurred, the slot status
>> in either BLINKINGOFF_STATE or OFF_STATE, turn it off unconditionally.
>> But if the slot status is in BLINKINGON_STATE and the slot is currently
>> empty, the slot status was staying in BLINKINGON_STATE.
>>
>> The message print like this:
>> pcieport 0000:00:01.5: pciehp: Slot(0-5): Attention button pressed
>> pcieport 0000:00:01.5: pciehp: Slot(0-5) Powering on due to button press
>> pcieport 0000:00:01.5: pciehp: Slot(0-5): Attention button pressed
>> pcieport 0000:00:01.5: pciehp: Slot(0-5): Button cancel
>> pcieport 0000:00:01.5: pciehp: Slot(0-5): Action canceled due to button press
>>
>> It cause the next Attention Button Pressed event become Button cancel
>> and missing the Presence Detect Changed event with this button press
>> though this button presses event is occurred after 5s.
>
> I see what you mean.
>
> pciehp's behavior is incorrect if the Attention Button is pressed
> on an unoccupied slot:
>
> Upon a button press, pciehp_queue_pushbutton_work() is scheduled to run
> after 5 seconds. It synthesizes a Presence Detect Changed event,
> whereupon pciehp_handle_presence_or_link_change() runs.
>
> Should the slot be empty, pciehp_handle_presence_or_link_change() just
> bails out and the state incorrectly remains in BLINKINGON_STATE.
>
>
>> --- a/drivers/pci/hotplug/pciehp_ctrl.c
>> +++ b/drivers/pci/hotplug/pciehp_ctrl.c
>> @@ -232,6 +232,7 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
>> */
>> mutex_lock(&ctrl->state_lock);
>> switch (ctrl->state) {
>> + case BLINKINGON_STATE:
>> case BLINKINGOFF_STATE:
>> cancel_delayed_work(&ctrl->button_work);
>> fallthrough;
>
> This solution has the disadvantage that a gratuitous "Card not present"
> message is emitted even if the slot is occupied.
>
Thank you for your advice.
I think when the "Card not present" is emitted, it may not consider the slot status
from the beginning. If the slot is in ON_STATE and is occupied, turn the slot off and then back on. The message is also emitted at first.
> I'd prefer the following simpler solution:
>
> diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
> index 529c348..e680444 100644
> --- 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 = POWEROFF_STATE;
> mutex_unlock(&ctrl->state_lock);
> return;
> }
>> Optionally the assignment can be made conditional on
> "if (ctrl->state == BLINKINGON_STATE)" for clarity.
>
> Likewise, a "Card not present" message can optionally be emitted here.
It should set crtl->state = OFF_STATE in direct and add cancel_delayed_work(&ctrl->button_work). And add message here looks a bit redundancy.
>
> Thanks,
>
> Lukas
>
Maybe I can rework to add like this to prevent the gratuitous message:
diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index 86fc9342be68..8dbf767a65ac 100644
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c
@@ -239,12 +239,6 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
case ON_STATE:
ctrl->state = POWEROFF_STATE;
mutex_unlock(&ctrl->state_lock);
- if (events & PCI_EXP_SLTSTA_DLLSC)
- ctrl_info(ctrl, "Slot(%s): Link Down\n",
- slot_name(ctrl));
- if (events & PCI_EXP_SLTSTA_PDC)
- ctrl_info(ctrl, "Slot(%s): Card not present\n",
- slot_name(ctrl));
pciehp_disable_slot(ctrl, SURPRISE_REMOVAL);
break;
default:
@@ -257,6 +251,12 @@ 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) {
mutex_unlock(&ctrl->state_lock);
+ if (events & PCI_EXP_SLTSTA_DLLSC)
+ ctrl_info(ctrl, "Slot(%s): Link Down\n",
+ slot_name(ctrl));
+ if (events & PCI_EXP_SLTSTA_PDC)
+ ctrl_info(ctrl, "Slot(%s): Card not present\n",
+ slot_name(ctrl));
return;
}
Thanks,
Wei
