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authorThomas Renninger <trenn@suse.de>2008-12-09 13:05:09 +0100
committerJesse Barnes <jbarnes@virtuousgeek.org>2008-12-09 14:59:24 -0800
commit2a42d9dba7842422ffb2c02e75288a8bc2fd5065 (patch)
treed9cfe4822696f60b6cd79683ea53174f7cb74730
parent3b5dd45e947ecd21491e1658fba7bb4bc4a54995 (diff)
downloadlinux-2.6.34-ux500-2a42d9dba7842422ffb2c02e75288a8bc2fd5065.tar.gz
PCIe: ASPM: Break out of endless loop waiting for PCI config bits to switch
Makes a Compaq 6735s boot reliably again. It used to hang in the loop on some boots. Give the link one second to train, otherwise break out of the loop and reset the previously set clock bits. Cc: stable@vger.kernel.org Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Matthew Garrett <mjg59@srcf.ucam.org> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
-rw-r--r--drivers/pci/pcie/aspm.c29
1 files changed, 26 insertions, 3 deletions
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 8f63f4c6b85..9aad608bcf3 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -16,6 +16,7 @@
#include <linux/pm.h>
#include <linux/init.h>
#include <linux/slab.h>
+#include <linux/jiffies.h>
#include <linux/pci-aspm.h>
#include "../pci.h"
@@ -161,11 +162,12 @@ static void pcie_check_clock_pm(struct pci_dev *pdev)
*/
static void pcie_aspm_configure_common_clock(struct pci_dev *pdev)
{
- int pos, child_pos;
+ int pos, child_pos, i = 0;
u16 reg16 = 0;
struct pci_dev *child_dev;
int same_clock = 1;
-
+ unsigned long start_jiffies;
+ u16 child_regs[8], parent_reg;
/*
* all functions of a slot should have the same Slot Clock
* Configuration, so just check one function
@@ -191,16 +193,19 @@ static void pcie_aspm_configure_common_clock(struct pci_dev *pdev)
child_pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP);
pci_read_config_word(child_dev, child_pos + PCI_EXP_LNKCTL,
&reg16);
+ child_regs[i] = reg16;
if (same_clock)
reg16 |= PCI_EXP_LNKCTL_CCC;
else
reg16 &= ~PCI_EXP_LNKCTL_CCC;
pci_write_config_word(child_dev, child_pos + PCI_EXP_LNKCTL,
reg16);
+ i++;
}
/* Configure upstream component */
pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, &reg16);
+ parent_reg = reg16;
if (same_clock)
reg16 |= PCI_EXP_LNKCTL_CCC;
else
@@ -212,12 +217,30 @@ static void pcie_aspm_configure_common_clock(struct pci_dev *pdev)
pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16);
/* Wait for link training end */
- while (1) {
+ /* break out after waiting for 1 second */
+ start_jiffies = jiffies;
+ while ((jiffies - start_jiffies) < HZ) {
pci_read_config_word(pdev, pos + PCI_EXP_LNKSTA, &reg16);
if (!(reg16 & PCI_EXP_LNKSTA_LT))
break;
cpu_relax();
}
+ /* training failed -> recover */
+ if ((jiffies - start_jiffies) >= HZ) {
+ dev_printk (KERN_ERR, &pdev->dev, "ASPM: Could not configure"
+ " common clock\n");
+ i = 0;
+ list_for_each_entry(child_dev, &pdev->subordinate->devices,
+ bus_list) {
+ child_pos = pci_find_capability(child_dev,
+ PCI_CAP_ID_EXP);
+ pci_write_config_word(child_dev,
+ child_pos + PCI_EXP_LNKCTL,
+ child_regs[i]);
+ i++;
+ }
+ pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, parent_reg);
+ }
}
/*