ethernet: T3802: not all NICs support reading speed/duplex settings in all states

Turns out an AX88179 USB 3.0 NIC does not support reading back the speed and
duplex settings in every operating state. While the NIC is beeing
initialized, reading the speed setting will return:

$ cat /sys/class/net/eth6/speed
cat: /sys/class/net/eth6/speed: Invalid argument

Thus if this happens, we simply tell the system that the current NIC speed
matches the requested speed and nothing is changed at this point in time.

1 files changed, 6 insertions, 3 deletions

diff --git a/python/vyos/ifconfig/ethernet.py b/python/vyos/ifconfig/ethernet.py
index 50e865203..d06b0a842 100644
--- a/python/vyos/ifconfig/ethernet.py
+++ b/python/vyos/ifconfig/ethernet.py
@@ -143,9 +143,12 @@ class EthernetIf(Interface):
                 # bail out early as nothing is to change
                 return
         else:
-            # read in current speed and duplex settings
-            cur_speed = read_file(f'/sys/class/net/{ifname}/speed')
-            cur_duplex = read_file(f'/sys/class/net/{ifname}/duplex')
+            # XXX: read in current speed and duplex settings
+            # There are some "nice" NICs like AX88179 which do not support
+            # reading the speed thus we simply fallback to the supplied speed
+            # to not cause any change here and raise an exception.
+            cur_speed = read_file(f'/sys/class/net/{ifname}/speed', speed)
+            cur_duplex = read_file(f'/sys/class/net/{ifname}/duplex', duplex)
             if (cur_speed == speed) and (cur_duplex == duplex):
                 # bail out early as nothing is to change
                 return