[Skiboot] [PATCH v2 1/9] core/pci: Return error on invalid power state transition

[Gavin Shan]

This returns error (OPAL_PARAMETER) when having invalid power state
transition requests. The invalid requests include: ON to ON, OFF to
OFF.

Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
---
 core/pcie-slot.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/core/pcie-slot.c b/core/pcie-slot.c
index 6854ef1..7fe3785 100644
--- a/core/pcie-slot.c
+++ b/core/pcie-slot.c
@@ -199,13 +199,13 @@ static int64_t pcie_slot_set_power_state(struct pci_slot *slot, uint8_t val)
 	uint32_t ecap;
 	uint16_t state;
 
+	if (slot->power_state == val)
+		return OPAL_PARAMETER;
+
 	/* Drop the request if functionality doesn't exist */
 	if (!(slot->slot_cap & PCICAP_EXP_SLOTCAP_PWCTRL))
 		return OPAL_SUCCESS;
 
-	if (slot->power_state == val)
-		return OPAL_SUCCESS;
-
 	pci_slot_set_state(slot, PCI_SLOT_STATE_SPOWER_START);
 	slot->power_state = val;
 	ecap = pci_cap(pd, PCI_CFG_CAP_ID_EXP, false);
-- 
2.1.0