[PATCH] pciehp: handle sticky power-fault status
This patch disables power fault, MRL sensor and presence detection
interrupts when a PCIe slot is powered-off and enables those
interrupts when it is powered-on again. This is necessary to prevent
the associated events from causing an endless cycle of interrupts
due to the power-fault bit, which stays set till power is restored
to the slot.
Signed-off-by: Thomas Schaefer <thomas.schaefer@kontron.com>
Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index ac1e495..77e5303 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -787,8 +787,13 @@
slot_cmd = (slot_ctrl & ~PWR_CTRL) | POWER_ON;
+ /* Enable detection that we turned off at slot power-off time */
if (!pciehp_poll_mode)
- slot_cmd = slot_cmd | HP_INTR_ENABLE;
+ slot_cmd = slot_cmd |
+ PWR_FAULT_DETECT_ENABLE |
+ MRL_DETECT_ENABLE |
+ PRSN_DETECT_ENABLE |
+ HP_INTR_ENABLE;
retval = pcie_write_cmd(slot, slot_cmd);
@@ -833,8 +838,18 @@
slot_cmd = (slot_ctrl & ~PWR_CTRL) | POWER_OFF;
+ /*
+ * If we get MRL or presence detect interrupts now, the isr
+ * will notice the sticky power-fault bit too and issue power
+ * indicator change commands. This will lead to an endless loop
+ * of command completions, since the power-fault bit remains on
+ * till the slot is powered on again.
+ */
if (!pciehp_poll_mode)
- slot_cmd = slot_cmd | HP_INTR_ENABLE;
+ slot_cmd = (slot_cmd &
+ ~PWR_FAULT_DETECT_ENABLE &
+ ~MRL_DETECT_ENABLE &
+ ~PRSN_DETECT_ENABLE) | HP_INTR_ENABLE;
retval = pcie_write_cmd(slot, slot_cmd);