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net: dsa: lan9303: Do not disable switch fabric port 0 at .probe

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Make the LAN9303 work when lan9303_probe() is called twice.

For some unknown reason the LAN9303 switch fail to forward data when switch
fabric port 0 TX is disabled during probe. (Write of LAN9303_MAC_TX_CFG_0
in lan9303_disable_processing_port().)

In that situation the switch fabric seem to receive frames, because the ALR
is learning addresses. But no frames are transmitted on any of the ports.

In our system lan9303_probe() is called twice, first time
dsa_register_switch() return -EPROBE_DEFER. As an experiment, modified the
code to skip writing LAN9303_MAC_TX_CFG_0, port 0 during the first probe.
Then the switch works as expected.

Resolve the problem by not calling lan9303_disable_processing_port() on
port 0 during probe. Ports 1 and 2 are still disabled.

Although unsatisfying that the exact failure mechanism is not known,
the patch should not cause any harm.

Signed-off-by: Egil Hjelmeland <privat@egil-hjelmeland.no>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Egil Hjelmeland 2017-10-24 17:14:10 +02:00 committed by David S. Miller
parent acfdf7eabe
commit 3c91b0c1de
1 changed files with 1 additions and 1 deletions
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2
drivers/net/dsa/lan9303-core.c
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@ -818,7 +818,7 @@ static int lan9303_disable_processing(struct lan9303 *chip)
{
int p;
for (p = 0; p < LAN9303_NUM_PORTS; p++) {
for (p = 1; p < LAN9303_NUM_PORTS; p++) {
int ret = lan9303_disable_processing_port(chip, p);
if (ret)