Re: [PATCH net-next v2 13/14] ravb: Update EMAC configuration mode comment

On 10/10/21 8:24 PM, Sergey Shtylyov wrote:

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Update EMAC configuration mode comment from "PAUSE prohibition"
to "EMAC Mode: PAUSE prohibition; Duplex; TX; RX; CRC Pass Through;
Promiscuous".

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Suggested-by: Sergey Shtylyov <redacted>
---
v1->v2:
   * No change
V1:
   * New patch.
---
   drivers/net/ethernet/renesas/ravb_main.c | 2 +-
   1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/renesas/ravb_main.c

b/drivers/net/ethernet/renesas/ravb_main.c
index 9a770a05c017..b78aca235c37 100644

--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c

@@ -519,7 +519,7 @@ static void ravb_emac_init_gbeth(struct

net_device

*ndev)

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   	/* Receive frame limit set register */
   	ravb_write(ndev, GBETH_RX_BUFF_MAX + ETH_FCS_LEN, RFLR);

-	/* PAUSE prohibition */
+	/* EMAC Mode: PAUSE prohibition; Duplex; TX; RX; CRC Pass Through;
+Promiscuous */

     Promiscuous mode, really? Why?!

This is TOE related,

I meant the context here is TOE register related. That is what I meant.

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    The promiscuous mode is supported by _all_ Ethernet controllers, I
think.

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and is recommendation from BSP team.

    On what grounds?

The reference implementation has this on. Any way it is good catch. 
I will turn it off and check.

by looking at the RJ LED's there is not much activity and packet statistics also show not much activity by default.

How can we check, it is overloading the controller? So that I can compare with and without this setting

   Maybe it doesn't get overloaded that simply, but definitely the promiscuous mode is not the thing
for the normal driver use...

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If you think it is wrong.
I can take this out. Please let me know. Currently the board is booting

and everything works without issues.

    Please do take it out. It'll needlessly overload the controller when
there's much traffic on the local network.

I can see much activity only on RJ45 LED's when I call tcpdump or by setting IP link set eth0 promisc on.
Otherwise there is no traffic at all.

   Sounds like the kernel initially sets the RX mode with IFF_PROMISC = 0 and thus clear ECMR.PRM but I don't
see where it does this? Could you instrument ravb_set_tx_mode() plz?

   Sorry, ravb_set_rx_mode(), of/c. :-)

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Regards,
Biju

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MBR, Sergey