1 files changed, 28 insertions, 0 deletions

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 245d2cdb4765..1812ae7698de 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2595,9 +2595,37 @@ void pci_fixup_device(enum pci_fixup_pass pass, struct pci_dev *dev)
 static int __init pci_apply_final_quirks(void)
 {
         struct pci_dev *dev = NULL;
+        u8 cls = 0;
+        u8 tmp;
+
+        if (pci_cache_line_size)
+                printk(KERN_DEBUG "PCI: CLS %u bytes\n",
+                       pci_cache_line_size << 2);
 
         while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
                 pci_fixup_device(pci_fixup_final, dev);
+                /*
+                 * If arch hasn't set it explicitly yet, use the CLS
+                 * value shared by all PCI devices.  If there's a
+                 * mismatch, fall back to the default value.
+                 */
+                if (!pci_cache_line_size) {
+                        pci_read_config_byte(dev, PCI_CACHE_LINE_SIZE, &tmp);
+                        if (!cls)
+                                cls = tmp;
+                        if (!tmp || cls == tmp)
+                                continue;
+
+                        printk(KERN_DEBUG "PCI: CLS mismatch (%u != %u), "
+                               "using %u bytes\n", cls << 2, tmp << 2,
+                               pci_dfl_cache_line_size << 2);
+                        pci_cache_line_size = pci_dfl_cache_line_size;
+                }
+        }
+        if (!pci_cache_line_size) {
+                printk(KERN_DEBUG "PCI: CLS %u bytes, default %u\n",
+                       cls << 2, pci_dfl_cache_line_size << 2);
+                pci_cache_line_size = cls;
         }
 
         return 0;