Re: bnx2: rx_fw_discards: BCM5716 sporadically drops packets when update to driver version 2.2.6

[maowenan <maowenan@huawei.com>]

On 2018/10/30 14:47, Mody, Rasesh wrote:
>> From: maowenan <maowenan@huawei.com>
>> Sent: Thursday, October 25, 2018 8:16 PM
>>
>> Hi，
>>
>> After I update version of bnx2 driver from 2.2.1 to 2.2.6, I find BCM5716
>> sporadically drops packets, which shows in rx_fw_discards.
>> C36-141-5:~ #  ethtool -S NIC0
>>
>> NIC statistics:
>>     rx_ucast_packets: 11902
>>
>>     rx_mcast_packets: 217
>>
>>     rx_bcast_packets: 4954320
>>
>>     rx_filtered_packets: 328793
>>
>>     rx_fw_discards: 2742
>>
>> C36-141-5:~ #
>>
>> 5s later:
>>
>> C36-141-5:~ #  ethtool -S NIC0
>>
>> NIC statistics:
>>     rx_ucast_packets: 11910
>>
>>     rx_mcast_packets: 217
>>
>>     rx_bcast_packets: 4958117
>>
>>     rx_filtered_packets: 328897
>>
>>     rx_fw_discards: 2750
>>
>> C36-141-5:~ #
>>
>> so rx_fw_discards: 2742-----> rx_fw_discards: 2750, lost 8 packets.
>>
>> the information of bnx2
>> C36-141-5:~ # modinfo bnx2
>> kernel/drivers/net/ethernet/broadcom/bnx2.ko
>>
>> firmware:       bnx2/bnx2-rv2p-09ax-6.0.17.fw
>>
>> firmware:       bnx2/bnx2-rv2p-09-6.0.17.fw
>>
>> firmware:       bnx2/bnx2-mips-09-6.2.1b.fw
>>
>> firmware:       bnx2/bnx2-rv2p-06-6.0.15.fw
>>
>> firmware:       bnx2/bnx2-mips-06-6.2.3.fw
>> version:        2.2.6
>>
>>
>> 1) Firstly, I check the patches from 2.2.1 to 2.2.6, below patch is interesting.
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id
>> =0021850d0417a4dc38ed871d929b651b87e2ead9
>> Do not enable filter SORT MODE in chip init routine. This patch addresses an
>> issue where BCM5716 sporadically drops packets when changing multicast list.
>>
>> diff --git a/drivers/net/ethernet/broadcom/bnx2.c
>> b/drivers/net/ethernet/broadcom/bnx2.c
>> index 8957eb5f4478..8c9a8b7787d2 100644
>> --- a/drivers/net/ethernet/broadcom/bnx2.c
>> +++ b/drivers/net/ethernet/broadcom/bnx2.c
>> @@ -4984,8 +4984,6 @@ bnx2_init_chip(struct bnx2 *bp)
>>
>>        bp->idle_chk_status_idx = 0xffff;
>>
>> -       bp->rx_mode = BNX2_EMAC_RX_MODE_SORT_MODE;
>> -
>>        /* Set up how to generate a link change interrupt. */
>>        BNX2_WR(bp, BNX2_EMAC_ATTENTION_ENA,
>> BNX2_EMAC_ATTENTION_ENA_LINK);
>>
>>
>> 2) Secondly, I revert this patch, after verify it, I find rx_fw_discards does not
>> increasing.
>> so I think this patch can fix current issue. But I'm not sure the issue of this
>> patch to fix will be reproduced?
>> I'm not convinced that what factor will trigger rx_fw_discards increasing?
>> And how to fix this?
> 
> Can you please reword your point above? i.e. what is working and what is not. I am not sure if I understand it completely.
> 
> Is the rx_fw_disacard count incrementing with 2.2.6 upstream driver on BCM5716? What is the kernel version?
> Which test is being run?


The case is based on BCM5716's driver version of 2.2.6, and both 3.10 and mainline kernel version exist this issue .
The testing seems like using one port of BCM5716 to receive packets, it can be found rx_fw_disacard increasing occasionally.
There is one patch in 2.2.6, 0021850d0417a4dc38ed871d929b651b87e2ead9, if I remove this patch, I can't reproduce this issue,
rx_fw_disacard doesn't increase.
So I don't know why this patch(0021850d0417a4dc38ed871d929b651b87e2ead9) can fix my problem(rx_fw_disacard increasing)?
If I remove this patch, how to fix the issue that the patch had resolved?

> 
>>
>> Thanks a lot.
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