Patch "PCI: pciehp: Cancel bringup sequence if card is not present" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    PCI: pciehp: Cancel bringup sequence if card is not present

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     pci-pciehp-cancel-bringup-sequence-if-card-is-not-pr.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 101b36ae53a3119b2c7e44b2549c1eb8f4c55b46
Author: Rongguang Wei <weirongguang@xxxxxxxxxx>
Date:   Fri May 12 10:15:18 2023 +0800

    PCI: pciehp: Cancel bringup sequence if card is not present
    
    [ Upstream commit e8afd0d9fccc27c8ad263db5cf5952cfcf72d6fe ]
    
    If a PCIe hotplug slot has an Attention Button, the normal hot-add flow is:
    
      - Slot is empty and slot power is off
      - User inserts card in slot and presses Attention Button
      - OS blinks Power Indicator for 5 seconds
      - After 5 seconds, OS turns on Power Indicator, turns on slot power, and
        enumerates the device
    
    Previously, if a user pressed the Attention Button on an *empty* slot,
    pciehp logged the following messages and blinked the Power Indicator
    until a second button press:
    
      [0.000] pciehp: Button press: will power on in 5 sec
      [0.001] # Power Indicator starts blinking
      [5.001] # 5 second timeout; slot is empty, so we should cancel the
                request to power on and turn off Power Indicator
    
      [7.000] # Power Indicator still blinking
      [8.000] # possible card insertion
      [9.000] pciehp: Button press: canceling request to power on
    
    The first button press incorrectly left the slot in BLINKINGON_STATE, so
    the second was interpreted as a "cancel power on" event regardless of
    whether a card was present.
    
    If the slot is empty, turn off the Power Indicator and return from
    BLINKINGON_STATE to OFF_STATE after 5 seconds, effectively canceling the
    request to power on.  Putting the slot in OFF_STATE also means the second
    button press will correctly request a slot power on if the slot is
    occupied.
    
    [bhelgaas: commit log]
    Link: https://lore.kernel.org/r/20230512021518.336460-1-clementwei90@xxxxxxx
    Fixes: d331710ea78f ("PCI: pciehp: Become resilient to missed events")
    Suggested-by: Lukas Wunner <lukas@xxxxxxxxx>
    Signed-off-by: Rongguang Wei <weirongguang@xxxxxxxxxx>
    Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
    Reviewed-by: Lukas Wunner <lukas@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index 529c348084401..32baba1b7f131 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;
 	}