From: Ricky Wu <en-wei.wu@canonical.com>
To: jesse.brandeburg@intel.com
Cc: anthony.l.nguyen@intel.com, intel-wired-lan@lists.osuosl.org,
davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, rickywu0421@gmail.com,
en-wei.wu@canonical.com
Subject: [PATCH v2 2/2] e1000e: fix link fluctuations problem
Date: Fri, 3 May 2024 18:18:36 +0800 [thread overview]
Message-ID: <20240503101836.32755-1-en-wei.wu@canonical.com> (raw)
As described in https://bugzilla.kernel.org/show_bug.cgi?id=218642,
Intel I219-LM reports link up -> link down -> link up after hot-plugging
the Ethernet cable.
The problem is because the unstable behavior of Link Status bit in
PHY Status Register of some e1000e NIC. When we re-plug the cable,
the e1000e_phy_has_link_generic() (called after the Link-Status-Changed
interrupt) has read this bit with 1->0->1 (1=link up, 0=link down)
and e1000e reports it to net device layer respectively.
This patch solves the problem by passing polling delays on
e1000e_phy_has_link_generic() so that it will not get the unstable
states of Link Status bit.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218642
Fixes: 7d3cabbcc86 ("e1000e: disable K1 at 1000Mbps for 82577/82578")
Signed-off-by: Ricky Wu <en-wei.wu@canonical.com>
---
In v2:
* Split the sleep codes part into PATCHSET [1/2]
---
drivers/net/ethernet/intel/e1000e/ich8lan.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c b/drivers/net/ethernet/intel/e1000e/ich8lan.c
index f9e94be36e97..68f5698a22b0 100644
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.c
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c
@@ -1428,7 +1428,17 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
* link. If so, then we want to get the current speed/duplex
* of the PHY.
*/
- ret_val = e1000e_phy_has_link_generic(hw, 1, 0, &link);
+ /* We've seen that I219-LM sometimes has link fluctuations
+ * (link up -> link down -> link up) after hot-plugging the cable.
+ * The problem is caused by the instability of the Link Status bit
+ * (BMSR_LSTATUS) in MII Status Register. The average time between
+ * the first link up and link down is between 3~4 ms.
+ * Increasing the iteration times and setting up the delay to
+ * 100ms (which is safe) solves the problem.
+ * This behavior hasn't been seen on other NICs and also not being
+ * documented in datasheet/errata.
+ */
+ ret_val = e1000e_phy_has_link_generic(hw, COPPER_LINK_UP_LIMIT, 100000, &link);
if (ret_val)
goto out;
--
2.40.1
next reply other threads:[~2024-05-03 10:18 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-03 10:18 Ricky Wu [this message]
2024-05-07 12:31 ` [PATCH v2 2/2] e1000e: fix link fluctuations problem Andrew Lunn
2024-05-08 5:05 ` [Intel-wired-lan] " Sasha Neftin
2024-05-09 9:13 ` Ruinskiy, Dima
2024-05-09 13:46 ` Andrew Lunn
2024-05-09 17:40 ` En-Wei WU
2024-05-10 9:55 ` Sasha Neftin
2024-05-10 12:32 ` Andrew Lunn
2024-05-13 6:04 ` Sasha Neftin
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=20240503101836.32755-1-en-wei.wu@canonical.com \
--to=en-wei.wu@canonical.com \
--cc=anthony.l.nguyen@intel.com \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=intel-wired-lan@lists.osuosl.org \
--cc=jesse.brandeburg@intel.com \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=rickywu0421@gmail.com \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).