PCI: Sleep rather than busy-wait for VPD access completion

[cascardo/linux.git] / drivers / pci / access.c

diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index 8449d6b..01b9d0a 100644 (file)
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -342,14 +342,15 @@ static size_t pci_vpd_size(struct pci_dev *dev, size_t old_size)
 static int pci_vpd_wait(struct pci_dev *dev)
 {
        struct pci_vpd *vpd = dev->vpd;
-       unsigned long timeout = jiffies + HZ/20 + 2;
+       unsigned long timeout = jiffies + msecs_to_jiffies(50);
+       unsigned long max_sleep = 16;
        u16 status;
        int ret;
 
        if (!vpd->busy)
                return 0;
 
-       for (;;) {
+       while (time_before(jiffies, timeout)) {
                ret = pci_user_read_config_word(dev, vpd->cap + PCI_VPD_ADDR,
                                                &status);
                if (ret < 0)
@@ -360,15 +361,16 @@ static int pci_vpd_wait(struct pci_dev *dev)
                        return 0;
                }
 
-               if (time_after(jiffies, timeout)) {
-                       dev_printk(KERN_DEBUG, &dev->dev, "vpd r/w failed.  This is likely a firmware bug on this device.  Contact the card vendor for a firmware update\n");
-                       return -ETIMEDOUT;
-               }
                if (fatal_signal_pending(current))
                        return -EINTR;
-               if (!cond_resched())
-                       udelay(10);
+
+               usleep_range(10, max_sleep);
+               if (max_sleep < 1024)
+                       max_sleep *= 2;
        }
+
+       dev_warn(&dev->dev, "VPD access failed.  This is likely a firmware bug on this device.  Contact the card vendor for a firmware update\n");
+       return -ETIMEDOUT;
 }
 
 static ssize_t pci_vpd_read(struct pci_dev *dev, loff_t pos, size_t count,