Differences

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--- operstate [2018/08/26 17:16] – rpjday
+++ operstate [2018/08/27 11:07] (current) – [Testing under sysfs] rpjday
@@ Line 66: / Line 66: @@
 ==== include/uapi/linux/if.h ====
+Possible values for ''netdev%%->%%operstate'':
 <code>
@@ Line 116: / Line 118: @@
 ===== Testing under sysfs =====
-Unplugging and plugging:
+Unplugging and plugging (administratively, the interface remains UP the whole time):
 <code>
@@ Line 150: / Line 152: @@
 </code>
-This should be set by ''dev_open()'', so it should be up regardless.
+This should be set by ''dev_open()'', so it should be up regardless. See usage [[https://elixir.bootlin.com/linux/latest/ident/__LINK_STATE_START|here]].
 ==== netif_oper_up() ====
-This is the important one related to plugging and unplugging:
+This is the important one related to plugging and unplugging (ignore the possibility of ''IF_OPER_UNKNOWN'' for now):
 <code>
@@ Line 169: / Line 171: @@
 </code>
 ==== netif_carrier_ok() ====
+This routine becomes important shortly:
 <code>
@@ Line 199: / Line 203: @@
         struct net_device *netdev = to_net_dev(dev);
-        if (netif_running(netdev))  // if IFF_UP, which should be true
+        if (netif_running(netdev))  // if __LINK_STATE_START, which should be true
                 return sprintf(buf, fmt_dec, !!netif_carrier_ok(netdev));
@@ Line 234: / Line 238: @@
 </code>
-which brings us back to who sets ''__LINK_STATE_NOCARRIER''.
+which brings us back to who sets ''%%__%%LINK_STATE_NOCARRIER''.
 ==== Setting/detecting carrier ====
@@ Line 277: / Line 281: @@
 EXPORT_SYMBOL(netif_carrier_off);
 </code>
+So who calls ''netif_carrier_off()''? Apparently, lots of people.