ASPM: Use msleep instead of cpu_relax during link retraining
The cpu_relax() function can be a noop on certain architectures
like IA-64 when CPU threads are disabled, so use msleep instead
during link retraining busy/wait loop.
Introduce define LINK_RETRAIN_TIMEOUT instead of hard-coding
timeout in pcie_aspm_configure_common_clock.
Signed-off-by: Andrew Patterson <andrew.patterson@xxxxxx>
---
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index e361c7d..c00fd65 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -17,6 +17,7 @@
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
+#include <linux/delay.h>
#include <linux/pci-aspm.h>
#include "../pci.h"
@@ -70,6 +71,8 @@ static const char *policy_str[] = {
[POLICY_POWERSAVE] = "powersave"
};
+#define LINK_RETRAIN_TIMEOUT HZ
+
static int policy_to_aspm_state(struct pci_dev *pdev)
{
struct pcie_link_state *link_state = pdev->link_state;
@@ -217,16 +220,18 @@ 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 */
- /* break out after waiting for 1 second */
+ /* break out after waiting for timeout */
start_jiffies = jiffies;
- while ((jiffies - start_jiffies) < HZ) {
+ for (;;) {
pci_read_config_word(pdev, pos + PCI_EXP_LNKSTA, ®16);
if (!(reg16 & PCI_EXP_LNKSTA_LT))
break;
- cpu_relax();
+ if ((jiffies - start_jiffies) >= LINK_RETRAIN_TIMEOUT)
+ break;
+ msleep(1);
}
/* training failed -> recover */
- if ((jiffies - start_jiffies) >= HZ) {
+ if ((jiffies - start_jiffies) >= LINK_RETRAIN_TIMEOUT) {
dev_printk (KERN_ERR, &pdev->dev, "ASPM: Could not configure"
" common clock\n");
i = 0;
--
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