eth0 is dropping packets

Subramanyan Krishnan

Other Parts Discussed in Thread: AM3352

Hi,

I am working on a board based on TI Sitara 3352. It has dual Ethernet port. We are using Sitara SDK Version 6.00.00. The firmware is configured for Dual MAC mode. I have connected eth0 of the board to the LAN and eth1 to a device (like a PC). I have dhcpd running on eth1 to form a crash net. I have connected eth1 to a PC.

The network link appears to be dropping packets for eth0 as show in the ifconfig dump below (919 packets dropped). eth0 is connected to LAN. Any idea why that could be happening ? We are seeing this in both the switch mode and dual mac mode.

eth0 Link encap:Ethernet HWaddr C4:ED:BA:82:41:66

inet addr:192.168.61.85 Bcast:192.168.61.255 Mask:255.255.255.0

UP BROADCAST MULTICAST MTU:1500 Metric:1

RX packets:5228 errors:0 dropped:919 overruns:0 frame:0

TX packets:5143 errors:0 dropped:2 overruns:0 carrier:0

collisions:0 txqueuelen:1000

RX bytes:2923379 (2.7 MiB) TX bytes:1190073 (1.1 MiB)

Could this be a firmware issue (driver?) or a board design issue ?

Thanks and Regards,

Subbu

over 10 years ago

0 Biser Gatchev-XID over 10 years ago

TI__Guru**** 393215 points

Hi Subbu,

What is your hardware configuration - MAC interface, PHY used?

0 Subramanyan Krishnan over 10 years ago in reply to Biser Gatchev-XID

Intellectual 520 points

Hi Biser,

Thanks for the quick response.

Qualcomm AR8033-AL1B/1B-R is used in the board.

Regards,

Subbu

0 Biser Gatchev-XID over 10 years ago in reply to Subramanyan Krishnan

TI__Guru**** 393215 points

Unfortunately Qualcomm datasheets are not publicly available, so I cannot say anything on the HW side. This PHY hasn't been used in any of the AM335X reference designs.

0 Subramanyan Krishnan over 10 years ago in reply to Biser Gatchev-XID

Intellectual 520 points

Hi Biser,

Okay. Thanks. I have contacted the hardware manufacturer to check this issue. Are there any posts in the past where other have encountered a similar issue ?

Thanks and Regards,

Subbu

0 Biser Gatchev-XID over 10 years ago in reply to Subramanyan Krishnan

TI__Guru**** 393215 points

This has been observed with bad PCB routing in RMII mode, and could also happen for the same reason with RGMII I think.

0 -DK- over 10 years ago in reply to Biser Gatchev-XID

TI__Mastermind 27890 points

Biser Gatchev-XID said:

This has been observed with bad PCB routing in RMII mode, and could also happen for the same reason with RGMII I think.

Correct. In fact RGMII is much more sensitive to layout and timing issues due to the higher clocking rate (50MHz vs 125MHz).

Do you see the same behavior when you connect the same systems @ 100Mb and 10Mb?

0 Paul Chang over 10 years ago in reply to -DK-

Prodigy 10 points

Hi DK & Biser, I am Sabbu's coworker. AM3352 is running at 600MHz. We are using two Micrel KSZ8081 10/100Mbps PHY and MII interface connecting to AM3352. The LAN interface clock is derived from KSZ8081 with a 25MHz crystal. Wish these information is a help on investigating the root cause. Thanks for your valuable advise.

Paul

0 Subramanyan Krishnan over 10 years ago in reply to Paul Chang

Intellectual 520 points

Hi Biser, DK,

Paul Chang has added details on the hardware. Did you have any feedback on that information.

Do you know of implementations running well with the hardware configuration that Paul Chang has given.

As per your earlier posts, are you suggesting that PCB routing could be the only issue here ?

Thanks and Regards,

Subbu

0 -DK- over 10 years ago in reply to Subramanyan Krishnan

TI__Mastermind 27890 points

Could you answer my question? Do you see the same issue across all link speeds?

0 Louis Liu over 10 years ago

Prodigy 10 points

Hi,

We observed similar problem with linux running on TI EVM Starker Kit (Precision) Rev 1.2B.
For clarification, we loaded the pre-build images and the unmodified ti-sdk root-filesystem from SDK 06.00.
The network is running with 100M BaseT connection.

After powering up, system loaded default matrix-browser QT application. We clicked on the browser icon, and than clicked the shortcuts and loaded a few web pages. After running for 1~2 minute, we observed some packet lose from ifconfig already.

Here is the message from ifconfig:
============================
root@am335x-evm:~# ifconfig eth0
eth0 Link encap:Ethernet HWaddr BC:6A:29:53:C5:6C
inet addr:192.168.0.183 Bcast:0.0.0.0 Mask:255.255.255.0
UP BROADCAST RUNNING ALLMULTI MULTICAST MTU:1500 Metric:1
RX packets:3477 errors:0 dropped:582 overruns:0 frame:0
TX packets:1281 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1670763 (1.5 MiB) TX bytes:218265 (213.1 KiB)
============================

Any ideas ?

Louis

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eth0 is dropping packets