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authorGavin Shan <gwshan@linux.vnet.ibm.com>2016-10-14 15:26:01 +1100
committerStewart Smith <stewart@linux.vnet.ibm.com>2016-10-17 10:33:55 +1100
commitb0e5149417b310df7dd62c5daaec678a18845791 (patch)
tree8bdde8b531210481e5f17db75c4f5468319cded1
parentc47dfe59d8c15991494f425764cb99f4e59af36d (diff)
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core/pci: Return slot cached power state
We should return cached power state instead of retrieving it from hardware, meaning we're allowed to have the situation: the power is off in software, but it's on in hardware when the built-in power control functionality is ignored for some reasons (e.g. surprise hotplug support). Otherwise, the adapter behind the slot won't be probed in PCI hot add path. This returns the cached power state so that OS sees synchronised power and PCI slot hotplug state (added/removed). Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com> Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
-rw-r--r--core/pcie-slot.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/core/pcie-slot.c b/core/pcie-slot.c
index 711e2e2..fed3462 100644
--- a/core/pcie-slot.c
+++ b/core/pcie-slot.c
@@ -90,11 +90,15 @@ static int64_t pcie_slot_get_link_state(struct pci_slot *slot,
static int64_t pcie_slot_get_power_state(struct pci_slot *slot __unused,
uint8_t *val)
{
- /* The power is always on if no functionality is supported */
- if (!(slot->slot_cap & PCICAP_EXP_SLOTCAP_PWCTRL))
- *val = PCI_SLOT_POWER_ON;
- else
- *val = slot->power_state;
+ /* We should return the cached power state that is same to
+ * the PCI slot hotplug state (added/removed). Otherwise,
+ * the OS will see mismatched states, causing the adapter
+ * behind the slot can't be probed successfully on request
+ * of hot add. So we could run into the situation where the
+ * OS sees power-off but it's on in hardware.
+ */
+ *val = slot->power_state;
+
return OPAL_SUCCESS;
}