[PATCH] lspci: Decode PCIe Link registers only for devices with links

[Bjorn Helgaas <bhelgaas@xxxxxxxxxx>]

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@xxxxxxxxxx>
---
 ls-caps.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/ls-caps.c b/ls-caps.c
index 752a771..be19d38 100644
--- 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);
 }

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