netpoll: Introduce netpoll_carrier_timeout kernel option

Some PHYs require longer timeouts for carrier detection, and
auto-negotiation process may take indefinite amount of time.

It may be inconvenient to force longer timeouts for sane PHYs,
so let's introduce a kernel command line option.

Since we're using module_param(), the option also can be
changed in runtime.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index d77fbd8b79ac..9347f4ad4342 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1531,6 +1531,11 @@ and is between 256 and 4096 characters. It is defined in the file
                         symbolic names: lapic and ioapic
                         Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
 
+        netpoll.carrier_timeout=
+                        [NET] Specifies amount of time (in seconds) that
+                        netpoll should wait for a carrier. By default netpoll
+                        waits 4 seconds.
+
         no387           [BUGS=X86-32] Tells the kernel to use the 387 maths
                         emulation library even if a 387 maths coprocessor
                         is present.