| Message ID | 20171024151410.28494-1-privat@egil-hjelmeland.no |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net-next] net: dsa: lan9303: Do not disable switch fabric port 0 at .probe | expand |
On Tue, Oct 24, 2017 at 05:14:10PM +0200, Egil Hjelmeland wrote: > 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. I agree about this being unsatisfying, but as you said, it fixed your issue, and it probably does not cause other issues. Reviewed-by: Andrew Lunn <andrew@lunn.ch> Andrew
From: Egil Hjelmeland <privat@egil-hjelmeland.no> Date: Tue, 24 Oct 2017 17:14:10 +0200 > 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> Applied.
diff --git a/drivers/net/dsa/lan9303-core.c b/drivers/net/dsa/lan9303-core.c index 87f919f0e641..4c412bd52319 100644 --- a/drivers/net/dsa/lan9303-core.c +++ b/drivers/net/dsa/lan9303-core.c @@ -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)
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> --- drivers/net/dsa/lan9303-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)