[PATCH] PCI Express Hotplug: clear sticky power-fault bit
Per the PCI Express spec, the power-fault-detected bit in the
slot status register can be set anytime hardware detects a power
fault, regardless of whether the slot has a device populated in
it or not. This bit is sticky and must be explicitly cleared.
This patch is needed to allow hot-add after such a power fault
has been detected.
Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 2387e75..0b8b26b 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -750,7 +750,7 @@
{
struct php_ctlr_state_s *php_ctlr = slot->ctrl->hpc_ctlr_handle;
u16 slot_cmd;
- u16 slot_ctrl;
+ u16 slot_ctrl, slot_status;
int retval = 0;
@@ -767,6 +767,14 @@
return -1;
}
+ /* Clear sticky power-fault bit from previous power failures */
+ hp_register_read_word(php_ctlr->pci_dev,
+ SLOT_STATUS(slot->ctrl->cap_base), slot_status);
+ slot_status &= PWR_FAULT_DETECTED;
+ if (slot_status)
+ hp_register_write_word(php_ctlr->pci_dev,
+ SLOT_STATUS(slot->ctrl->cap_base), slot_status);
+
retval = hp_register_read_word(php_ctlr->pci_dev, SLOT_CTRL(slot->ctrl->cap_base), slot_ctrl);
if (retval) {