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Wed, 11 Feb 2026 18:29:12 +0000 (UTC) X-Virus-Scanned: amavis at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavis, port 10024) with ESMTP id DUcSFpbrvJAx for ; Wed, 11 Feb 2026 18:29:12 +0000 (UTC) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=172.105.4.254; helo=tor.source.kernel.org; envelope-from=helgaas@kernel.org; receiver= DMARC-Filter: OpenDMARC Filter v1.4.2 smtp2.osuosl.org CE9A340073 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org CE9A340073 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by smtp2.osuosl.org (Postfix) with ESMTPS id CE9A340073 for ; Wed, 11 Feb 2026 18:29:11 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id C475860018; Wed, 11 Feb 2026 18:29:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 507CFC4CEF7; Wed, 11 Feb 2026 18:29:10 +0000 (UTC) Date: Wed, 11 Feb 2026 12:29:09 -0600 From: Bjorn Helgaas To: Harshank Matkar Cc: "intel-wired-lan@lists.osuosl.org" , "netdev@vger.kernel.org" , "tony.nguyen@intel.com" , "davem@davemloft.net" , "kuba@kernel.org" , "pabeni@redhat.com" , "edumazet@google.com" , "linux-kernel@vger.kernel.org" Message-ID: <20260211182909.GA117627@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260210203332.23200-1-harshankmatkar1304@outlook.com> X-Mailman-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770834550; bh=FkTdMrzfnWOa65M7TOxVOTewRFDuBbrSyTDkM7TTM8w=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=ihi46+2ENQiAMifT2Lwhf/yFa/G83yY9BjSdarvUEs+XcVzxfI+w05QH04NLlMp0v 44hlBE/eE0wfizEO2hpc3uOb9+MU2yNXFctF3UZ14tUxQhcQdGA9ImtLD+ewuTLLcA 7Gms8XyrzbWAPve/KSNRv5/gHcsC/YWNMqzxlEAQrjNTP+Atlg3RmmhshTFiw+hwRY IGqizqdeHOJe4/B7D3oCPwH4+azvPI89LhaJmhtW97tIzFamykfTgd/rmPY/jw/SqF jWoxRbhpyre9gOys2dhtDuzF9RoTzddsb6XliZydSW2JA39prYpok2l+VRtNsIO3qE 9TUrdcrz+HFkw== X-Mailman-Original-Authentication-Results: smtp2.osuosl.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org X-Mailman-Original-Authentication-Results: smtp2.osuosl.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=ihi46+2E Subject: Re: [Intel-wired-lan] [PATCH] igc: Add PCIe link recovery for I225/I226 X-BeenThere: intel-wired-lan@osuosl.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Intel Wired Ethernet Linux Kernel Driver Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-wired-lan-bounces@osuosl.org Sender: "Intel-wired-lan" On Tue, Feb 10, 2026 at 08:34:02PM +0000, Harshank Matkar wrote: > From: Harshank Matkar > > When ASPM L0s transitions occur on Intel I225/I226 controllers, > transient PCIe link instability can cause register read failures > (0xFFFFFFFF responses). At the PCIe level, the failure is some uncorrectable PCIe error like a Completion Timeout or Unsupported Request. The 0xFFFFFFFF response is implementation-specific behavior determined by the Root Complex design. > Implement a multi-layer recovery strategy: > 1. Immediate retries: 3 attempts with 100-200μs delays > 2. Link retraining: Trigger PCIe link retraining via capabilities > 3. Device detachment: Only as last resort after max attempts > > The recovery mechanism includes rate limiting, maximum attempt > tracking, and device presence validation to prevent false detaches > on transient ASPM glitches while maintaining safety through > bounded retry limits. I assume the glitch is a hardware erratum and should be documented as such by Intel, although it's possible ASPM L0s isn't configured correctly. If it's a hardware erratum, I think you should use a quirk to disable L0s on these devices, e.g., pci_disable_link_state(pdev, PCIE_LINK_STATE_L0S). Even if this patch allows recovery, the PCIe errors will be logged and reported via AER, which will be confusing to users. Bjorn