netdev - Re: [REGRESSION] e1000e: RX stops after link down/up on Intel 8086:550a since v6.12.43 (fixed by suspend/resume)

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Message-ID: <20260113182400.723e34a1@kernel.org>
Date: Tue, 13 Jan 2026 18:24:00 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: "Wenger Jeremie (EDU)" <jeremie.wenger@....ge.ch>,
 intel-wired-lan@...ts.osuosl.org
Cc: "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Przemek
 Kitszel <przemyslaw.kitszel@...el.com>, Tony Nguyen
 <anthony.l.nguyen@...el.com>
Subject: Re: [REGRESSION] e1000e: RX stops after link down/up on Intel
 8086:550a since v6.12.43 (fixed by suspend/resume)

Thanks for the report, I'm adding the relevant people to CC now.
Please try to consult the MAINTAINERS file next time 'cause networking
is a bit too big for the right people to always notice reports.

My best guess below..

On Fri, 9 Jan 2026 09:40:34 +0000 Wenger Jeremie (EDU) wrote:
> Hello,
> 
> I would like to report a regression in the e1000e driver affecting an Intel integrated Ethernet controller.
> 
> Hardware:
> Intel Ethernet controller  [8086:550a]
> Driver: e1000e
> 
> Summary:
> - RX stops working after an Ethernet link down/up (unplug/replug cable).
> - TX still works. A system suspend/resume reliably restores RX.
> 
> Regression range:
> - Working: v6.12.22
> - Broken: v6.12.43 .. v6.18.3 (tested on Debian 12 backports, Debian 13, Debian sid). v6.18.3 is the most recent kernel tested so far, so the regression is likely still present in newer kernels.

Judging by the range seems like it has to be efaaf344bc2917cb
Would you be able to try building a kernel with that commit reverted?

> Symptoms:
> - Link is detected (1Gbps, full duplex).
> - DHCP DISCOVER frames are transmitted (confirmed via external packet capture).
> - No packets are received (no DHCP OFFER, RX appears dead).
> - Booting with the cable plugged works.
> - The issue is triggered only after unplugging and replugging the cable.
> - A suspend/resume cycle restores RX immediately.
> - Using a USB Ethernet adapter (r8152) on the same network works correctly.
>  
> Reproduction steps:
> - Boot with Ethernet cable plugged.
> - Verify network connectivity works.
> - Unplug the Ethernet cable.
> - Plug the Ethernet cable back in.
> - Observe that RX no longer works (no DHCP OFFER).
> - Suspend/resume the system → RX works again.
>  
> This suggests that the PHY or RX path is not correctly reinitialized on link up after a link down event, while the resume path performs a more complete reset.
> 
> I can provide additional logs, ethtool statistics, or test patches if needed.
> 
> 
> Best regards,
> 
> Jérémie Wenger