From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 278DE434E5D; Tue, 21 Jul 2026 20:22:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784665322; cv=none; b=Muqo4wYTrXvKMgV/6vLrIGuWv53CoHprAfYKEDGXv5bC3mVX9l0LQLZkY4Me/YWAfum2wpAdX8YNSb9RKqD6c3QkDo4hoI/tkAoS8kyo/RdimGNoQfwwjJuxFc0yBe+0Fplr47kISdeVV24vH/LbCMHvid174ge0SFimmMZkGi0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784665322; c=relaxed/simple; bh=gG7ez8vySpi77gTIRUZGn5V4ir5U1EtDO2FkfknA6eE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OyBF/8HRGhvbVhCIiiY/xQD5dktL011koyjTBbgJRZtVd/7xBLfkdaUViy162fY1veZPzkVEYrmPzDL8wfqjWuSkS0GUUkW/ISohumsheAGA1VRfQgIjalFqspj4aaeO92UISuZacoVykq4cyL5CMYWwud4NJBtpZXJjQxRjPdE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=kxTww/nu; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="kxTww/nu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B40531F000E9; Tue, 21 Jul 2026 20:22:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784665321; bh=Y8DjxKE7j5iW4kDv0sHttQMmTfqBIPzmPZU6TlwUdi0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kxTww/nutrfovjKVSqxO5QOKTbQ4Y2I0bRPbylC/9PyP0jAfUN/OOxtb1a/j32mC/ 1tUgIHv+NWGA7+fhmf7ZhCgOvY9gRUcdBCPpCeTGIfANZZiAIS4E2F9BA5S5eZyJDe um3fT6rPZUv8SeK0NtHnzAviOO07IGHFeeHw0JfE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Maciej W. Rozycki" , Bjorn Helgaas , Alok Tiwari , Sasha Levin Subject: [PATCH 6.6 0259/1266] PCI: Always lift 2.5GT/s restriction in PCIe failed link retraining Date: Tue, 21 Jul 2026 17:11:36 +0200 Message-ID: <20260721152447.611391112@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152441.786066624@linuxfoundation.org> References: <20260721152441.786066624@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Maciej W. Rozycki commit 72780f7964684939d7d2f69c348876213b184484 upstream. Discard Vendor:Device ID matching in the PCIe failed link retraining quirk and ignore the link status for the removal of the 2.5GT/s speed clamp, whether applied by the quirk itself or the firmware earlier on. Revert to the original target link speed if this final link retraining has failed. This is so that link training noise in hot-plug scenarios does not make a link remain clamped to the 2.5GT/s speed where an event race has led the quirk to apply the speed clamp for one device, only to leave it in place for a subsequent device to be plugged in. Refer to the Link Capabilities register directly for the maximum link speed determination so as to streamline backporting. Fixes: a89c82249c37 ("PCI: Work around PCIe link training failures") Signed-off-by: Maciej W. Rozycki Signed-off-by: Bjorn Helgaas Tested-by: Alok Tiwari Cc: stable@vger.kernel.org # v6.5+ Link: https://patch.msgid.link/alpine.DEB.2.21.2512080331530.49654@angie.orcam.me.uk [ Update for missing PCIe link speed helpers for 6.6.y. ] Signed-off-by: Maciej W. Rozycki Signed-off-by: Sasha Levin --- drivers/pci/quirks.c | 51 +++++++++++++++++--------------------------- 1 file changed, 20 insertions(+), 31 deletions(-) diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 5df3a6ea660187..28fa0a9b18c824 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -68,11 +68,10 @@ * Restrict the speed to 2.5GT/s then with the Target Link Speed field, * request a retrain and check the result. * - * If this turns out successful and we know by the Vendor:Device ID it is - * safe to do so, then lift the restriction, letting the devices negotiate - * a higher speed. Also check for a similar 2.5GT/s speed restriction the - * firmware may have already arranged and lift it with ports that already - * report their data link being up. + * If this turns out successful, or where a 2.5GT/s speed restriction has + * been previously arranged by the firmware and the port reports its link + * already being up, lift the restriction, in a hope it is safe to do so, + * letting the devices negotiate a higher speed. * * Otherwise revert the speed to the original setting and request a retrain * again to remove any residual state, ignoring the result as it's supposed @@ -83,12 +82,9 @@ */ int pcie_failed_link_retrain(struct pci_dev *dev) { - static const struct pci_device_id ids[] = { - { PCI_VDEVICE(ASMEDIA, 0x2824) }, /* ASMedia ASM2824 */ - {} - }; - u16 lnksta, lnkctl2; + u16 lnksta, lnkctl2, oldlnkctl2; int ret = -ENOTTY; + u32 lnkcap; if (!pci_is_pcie(dev) || !pcie_downstream_port(dev) || !pcie_cap_has_lnkctl2(dev) || !dev->link_active_reporting) @@ -96,10 +92,9 @@ int pcie_failed_link_retrain(struct pci_dev *dev) pcie_capability_read_word(dev, PCI_EXP_LNKCTL2, &lnkctl2); pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta); + oldlnkctl2 = lnkctl2; if ((lnksta & (PCI_EXP_LNKSTA_LBMS | PCI_EXP_LNKSTA_DLLLA)) == PCI_EXP_LNKSTA_LBMS) { - u16 oldlnkctl2 = lnkctl2; - pci_info(dev, "broken device, retraining non-functional downstream link at 2.5GT/s\n"); lnkctl2 &= ~PCI_EXP_LNKCTL2_TLS; @@ -107,35 +102,29 @@ int pcie_failed_link_retrain(struct pci_dev *dev) pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, lnkctl2); ret = pcie_retrain_link(dev, false); - if (ret) { - pci_info(dev, "retraining failed\n"); - pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, - oldlnkctl2); - pcie_retrain_link(dev, true); - return ret; - } - - pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta); + if (ret) + goto err; } - if ((lnksta & PCI_EXP_LNKSTA_DLLLA) && - (lnkctl2 & PCI_EXP_LNKCTL2_TLS) == PCI_EXP_LNKCTL2_TLS_2_5GT && - pci_match_id(ids, dev)) { - u32 lnkcap; - + pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &lnkcap); + if ((lnkctl2 & PCI_EXP_LNKCTL2_TLS) == PCI_EXP_LNKCTL2_TLS_2_5GT && + (lnkcap & PCI_EXP_LNKCAP_SLS) != PCI_EXP_LNKCAP_SLS_2_5GB) { pci_info(dev, "removing 2.5GT/s downstream link speed restriction\n"); - pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &lnkcap); lnkctl2 &= ~PCI_EXP_LNKCTL2_TLS; lnkctl2 |= lnkcap & PCI_EXP_LNKCAP_SLS; pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, lnkctl2); ret = pcie_retrain_link(dev, false); - if (ret) { - pci_info(dev, "retraining failed\n"); - return ret; - } + if (ret) + goto err; } + return ret; +err: + pci_info(dev, "retraining failed\n"); + pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, oldlnkctl2); + + pcie_retrain_link(dev, true); return ret; } -- 2.53.0