lspci: Decode PCIe Link registers only for devices with links

Root Complex Integrated Endpoints and Root Complex Event Collectors do not
have links and are not permitted to implement Link or Link 2 registers,
per PCIe spec r3.0, sec 1.3.2.3.  Decoding them is useless and misleading.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/ls-caps.c b/ls-caps.c
index 752a7713e34fdd1f5d8dc5a6c657b21bdc20e15f..be19d386829a2226af926f9fd9ac7f1c2085f7c9 100644 (file)
--- a/ls-caps.c
+++ b/ls-caps.c
@@ -1074,6 +1074,7 @@ cap_express(struct device *d, int where, int cap)
   int type = (cap & PCI_EXP_FLAGS_TYPE) >> 4;
   int size;
   int slot = 0;
+  int link = 1;
 
   printf("Express ");
   if (verbose >= 2)
@@ -1104,9 +1105,11 @@ cap_express(struct device *d, int where, int cap)
       printf("PCI/PCI-X to PCI-Express Bridge");
       break;
     case PCI_EXP_TYPE_ROOT_INT_EP:
+      link = 0;
       printf("Root Complex Integrated Endpoint");
       break;
     case PCI_EXP_TYPE_ROOT_EC:
+      link = 0;
       printf("Root Complex Event Collector");
       break;
     default:
@@ -1125,7 +1128,8 @@ cap_express(struct device *d, int where, int cap)
     return;
 
   cap_express_dev(d, where, type);
-  cap_express_link(d, where, type);
+  if (link)
+    cap_express_link(d, where, type);
   if (slot)
     cap_express_slot(d, where);
   if (type == PCI_EXP_TYPE_ROOT_PORT)
@@ -1141,7 +1145,8 @@ cap_express(struct device *d, int where, int cap)
     return;
 
   cap_express_dev2(d, where, type);
-  cap_express_link2(d, where, type);
+  if (link)
+    cap_express_link2(d, where, type);
   if (slot)
     cap_express_slot2(d, where);
 }