[PATCH] lspci: Don't report PCIe link downgrades for downstream ports

[Bjorn Helgaas <helgaas@kernel.org>]

From: Bjorn Helgaas <bhelgaas@google.com>

After b47b5bd408e1 ("lspci: Report if the PCIe link speed/width is full or
downgraded"), we report "downgraded" or "ok" for PCIe links operating at
lower speed or width than they're capable of:

  LnkCap: Port #1, Speed 8GT/s, Width x1, ASPM L1, Exit Latency L1 <16us
  LnkSta: Speed 5GT/s (downgraded), Width x1 (ok)

Previously we did this for both ends of the link, but I don't think it's
very useful for Downstream Ports (the upstream end of the link) because we
claim the link is downgraded even if (1) there's no device on the other end
or (2) the other device doesn't support anything faster/wider.

Drop the "downgraded" reporting for Downstream Ports.  If there is a device
below, we'll still complain at that end if it supports a faster/wider link
than is available.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 ls-caps.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/ls-caps.c b/ls-caps.c
index db56556..dd17c6b 100644
--- a/ls-caps.c
+++ b/ls-caps.c
@@ -758,13 +758,16 @@ static char *link_speed(int speed)
     }
 }
 
-static char *link_compare(int sta, int cap)
+static char *link_compare(int type, int sta, int cap)
 {
+  if ((type == PCI_EXP_TYPE_ROOT_PORT) || (type == PCI_EXP_TYPE_DOWNSTREAM) ||
+      (type == PCI_EXP_TYPE_PCIE_BRIDGE))
+    return "";
   if (sta < cap)
-    return "downgraded";
+    return " (downgraded)";
   if (sta > cap)
-    return "strange";
-  return "ok";
+    return " (strange)";
+  return " (ok)";
 }
 
 static char *aspm_support(int code)
@@ -837,11 +840,11 @@ static void cap_express_link(struct device *d, int where, int type)
   w = get_conf_word(d, where + PCI_EXP_LNKSTA);
   sta_speed = w & PCI_EXP_LNKSTA_SPEED;
   sta_width = (w & PCI_EXP_LNKSTA_WIDTH) >> 4;
-  printf("\t\tLnkSta:\tSpeed %s (%s), Width x%d (%s)\n",
+  printf("\t\tLnkSta:\tSpeed %s%s, Width x%d%s\n",
 	link_speed(sta_speed),
-	link_compare(sta_speed, cap_speed),
+	link_compare(type, sta_speed, cap_speed),
 	sta_width,
-	link_compare(sta_width, cap_width));
+	link_compare(type, sta_width, cap_width));
   printf("\t\t\tTrErr%c Train%c SlotClk%c DLActive%c BWMgmt%c ABWMgmt%c\n",
 	FLAG(w, PCI_EXP_LNKSTA_TR_ERR),
 	FLAG(w, PCI_EXP_LNKSTA_TRAIN),
-- 
2.25.1