All of lore.kernel.org
 help / color / mirror / Atom feed
From: Heyi Guo <guoheyi@linux.alibaba.com>
To: "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Joel Stanley <joel@jms.id.au>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Dylan Hung <dylan_hung@aspeedtech.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [Issue report] drivers/ftgmac100: DHCP occasionally fails during boot up or link down/up
Date: Tue, 15 Feb 2022 14:38:51 +0800	[thread overview]
Message-ID: <0e456c4d-aa22-4e7f-9b2c-3059fe840cb9@linux.alibaba.com> (raw)

Hi,

We are using Aspeed 2600 and found DHCP occasionally fails during boot 
up or link down/up. The DHCP client is systemd 247.6 networkd. Our 
network device is 2600 MAC4 connected to a RGMII PHY module.

Current investigation shows the first DHCP discovery packet sent by 
systemd-networkd might be corrupted, and sysmtemd-networkd will continue 
to send DHCP discovery packets with the same XID, but no other packets, 
as there is no IP obtained at the moment. However the server side will 
not respond with this serial of DHCP requests, until it receives some 
other packets. This situation can be recovered by another link down/up, 
or a "ping -I eth0 xxx.xxx.xxx.xxx" command to insert some other TX packets.

Navigating the driver code ftgmac.c, I've some question about the work 
flow from link down to link up. I think the flow is as below:

1. ftgmac100_open() will enable net interface with ftgmac100_init_all(), 
and then call phy_start()

2. When PHY is link up, it will call netif_carrier_on() and then 
adjust_link interface, which is ftgmac100_adjust_link() for ftgmac100

3. In ftgmac100_adjust_link(), it will schedule the reset work 
(ftgmac100_reset_task)

4. ftgmac100_reset_task() will then reset the MAC

I found networkd will start to send DHCP request immediately after 
netif_carrier_on() called in step 2, but step 4 will reset the MAC, 
which may potentially corrupt the sending packet.

Is there anything wrong in this flow? Or do I miss something?

Thanks,

Heyi


             reply	other threads:[~2022-02-15  6:39 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-15  6:38 Heyi Guo [this message]
2022-02-15 20:50 ` [Issue report] drivers/ftgmac100: DHCP occasionally fails during boot up or link down/up Andrew Lunn
2022-02-17  1:38   ` Heyi Guo
2022-02-19 10:08   ` Heyi Guo
2022-02-19 18:28     ` Andrew Lunn
2022-02-20 12:26       ` Heyi Guo
2022-02-21 22:09         ` Andrew Lunn
2022-02-22  3:09           ` Heyi Guo

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=0e456c4d-aa22-4e7f-9b2c-3059fe840cb9@linux.alibaba.com \
    --to=guoheyi@linux.alibaba.com \
    --cc=benh@kernel.crashing.org \
    --cc=davem@davemloft.net \
    --cc=dylan_hung@aspeedtech.com \
    --cc=joel@jms.id.au \
    --cc=kuba@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.