PCI: complain about devices that seem to be broken

If we can tell that a device isn't working correctly, we should tell
the user to make debugging easier.  Otherwise, it can take a lot of
work to determine whether the problem is in the driver, PCMCIA, PCI,
hardware, etc., as in http://bugzilla.kernel.org/show_bug.cgi?id=12006

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index c82548a..882bd8d 100644 (file)
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -174,14 +174,19 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
        pci_read_config_dword(dev, pos, &sz);
        pci_write_config_dword(dev, pos, l);
 
+       if (!sz)
+               goto fail;      /* BAR not implemented */
+
        /*
         * All bits set in sz means the device isn't working properly.
-        * If the BAR isn't implemented, all bits must be 0.  If it's a
-        * memory BAR or a ROM, bit 0 must be clear; if it's an io BAR, bit
-        * 1 must be clear.
+        * If it's a memory BAR or a ROM, bit 0 must be clear; if it's
+        * an io BAR, bit 1 must be clear.
         */
-       if (!sz || sz == 0xffffffff)
+       if (sz == 0xffffffff) {
+               dev_err(&dev->dev, "reg %x: invalid size %#x; broken device?\n",
+                       pos, sz);
                goto fail;
+       }
 
        /*
         * I don't know how l can have all bits set.  Copied from old code.
@@ -244,13 +249,17 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
                                   pos, res);
                }
        } else {
-               sz = pci_size(l, sz, mask);
+               u32 size = pci_size(l, sz, mask);
 
-               if (!sz)
+               if (!size) {
+                       dev_err(&dev->dev, "reg %x: invalid size "
+                               "(l %#x sz %#x mask %#x); broken device?",
+                               pos, l, sz, mask);
                        goto fail;
+               }
 
                res->start = l;
-               res->end = l + sz;
+               res->end = l + size;
 
                dev_printk(KERN_DEBUG, &dev->dev, "reg %x: %pR\n", pos, res);
        }