On system with 16 PCI express hotplug slots, customer complain every slot
will report "Command not completed in 1000 msec" during initialization.
Intel says that we should only wait command complete only for
Electromechanical Interlock Control
Power Controller Control
Power Indicator Control
Attention Indicator Control
System with AMD/Nvidia chipset have same problem.
So change to only wait when following bits get changed.
PCI_EXP_SLTCTL_EIC
PCI_EXP_SLTCTL_PCC
PCI_EXP_SLTCTL_PIC
PCI_EXP_SLTCTL_AIC
With that we could set 16 seconds during booting, later with 32 sockets system
with 64 pcie hotplug slots we could save 64 seconds.
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
---
drivers/pci/hotplug/pciehp_hpc.c | 11 ++++++-----
include/uapi/linux/pci_regs.h | 5 +++++
2 files changed, 11 insertions(+), 5 deletions(-)
Index: linux-2.6/drivers/pci/hotplug/pciehp_hpc.c
===================================================================
--- linux-2.6.orig/drivers/pci/hotplug/pciehp_hpc.c
+++ linux-2.6/drivers/pci/hotplug/pciehp_hpc.c
@@ -152,8 +152,8 @@ static void pcie_wait_cmd(struct control
static void pcie_write_cmd(struct controller *ctrl, u16 cmd, u16 mask)
{
struct pci_dev *pdev = ctrl_dev(ctrl);
+ u16 slot_ctrl, old_slot_ctrl;
u16 slot_status;
- u16 slot_ctrl;
mutex_lock(&ctrl->ctrl_lock);
@@ -181,9 +181,8 @@ static void pcie_write_cmd(struct contro
}
}
- pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
- slot_ctrl &= ~mask;
- slot_ctrl |= (cmd & mask);
+ pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &old_slot_ctrl);
+ slot_ctrl = (old_slot_ctrl & ~mask) | (cmd & mask);
ctrl->cmd_busy = 1;
smp_mb();
pcie_capability_write_word(pdev, PCI_EXP_SLTCTL, slot_ctrl);
@@ -191,7 +190,9 @@ static void pcie_write_cmd(struct contro
/*
* Wait for command completion.
*/
- if (!ctrl->no_cmd_complete) {
+ if (!ctrl->no_cmd_complete &&
+ ((PCI_EXP_SLTCTL_WAIT_MASK & old_slot_ctrl) !=
+ (PCI_EXP_SLTCTL_WAIT_MASK & slot_ctrl))) {
int poll = 0;
/*
* if hotplug interrupt is not enabled or command
Index: linux-2.6/include/uapi/linux/pci_regs.h
===================================================================
--- linux-2.6.orig/include/uapi/linux/pci_regs.h
+++ linux-2.6/include/uapi/linux/pci_regs.h
@@ -535,6 +535,11 @@
#define PCI_EXP_SLTCTL_PWR_OFF 0x0400 /* Power Off */
#define PCI_EXP_SLTCTL_EIC 0x0800 /* Electromechanical Interlock Control */
#define PCI_EXP_SLTCTL_DLLSCE 0x1000 /* Data Link Layer State Changed Enable */
+/* only need to wait command complete for hpc related */
+#define PCI_EXP_SLTCTL_WAIT_MASK (PCI_EXP_SLTCTL_EIC | \
+ PCI_EXP_SLTCTL_PCC | \
+ PCI_EXP_SLTCTL_PIC | \
+ PCI_EXP_SLTCTL_AIC)
#define PCI_EXP_SLTSTA 26 /* Slot Status */
#define PCI_EXP_SLTSTA_ABP 0x0001 /* Attention Button Pressed */
#define PCI_EXP_SLTSTA_PFD 0x0002 /* Power Fault Detected */
--
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