From: Rongguang Wei weirongguang@kylinos.cn
[ 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@163.com Fixes: d331710ea78f ("PCI: pciehp: Become resilient to missed events") Suggested-by: Lukas Wunner lukas@wunner.de Signed-off-by: Rongguang Wei weirongguang@kylinos.cn Signed-off-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Lukas Wunner lukas@wunner.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/hotplug/pciehp_ctrl.c | 8 ++++++++ 1 file changed, 8 insertions(+)
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; }