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>

1 files changed, 16 insertions, 7 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index c82548afcd5c..882bd8d29fe3 100644
--- 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);
         }