From nobody Mon Feb 9 11:07:35 2026 Received: from angie.orcam.me.uk (angie.orcam.me.uk [78.133.224.34]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 8F5F9443F; Sat, 10 Feb 2024 01:43:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.133.224.34 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707529440; cv=none; b=OlSvyn8wjt16tihq5cWVRxti2vz0SYyM2DqUktN4CN5dGH6/mQvMMdpj+RfFRkJm/Xz0O/FPeQCs1loCUWEqmgO7zFF09du8k9BMf6Zo//y7+iMWh88hUpCqXavgg8wX5McqdLL/4j+onCE77F7R5GTPCuTqrrjAaAwXR10hy3s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707529440; c=relaxed/simple; bh=ypgalr47NyKd3kk8vG+pac3NhdZUcsYOC4TTXs6GuPM=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=tLFlZBap3/HhVOexYwLZzu8czqJuoXA4ljCGztuhSn4A7ty8uE+bbQV5gphYsfhSp/KXvMLjvcKs1wBLN13dG5Xu5m94ypTjh3Y+Tsy6mPrM/djGKluRhKrWZA3yMGDc7KhE4w2IcE97oz3bYB2P8ilHMTq6PtlE8awxQvonEK4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=orcam.me.uk; spf=none smtp.mailfrom=orcam.me.uk; arc=none smtp.client-ip=78.133.224.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=orcam.me.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=orcam.me.uk Received: by angie.orcam.me.uk (Postfix, from userid 500) id 7C32392009D; Sat, 10 Feb 2024 02:43:50 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by angie.orcam.me.uk (Postfix) with ESMTP id 7524092009B; Sat, 10 Feb 2024 01:43:50 +0000 (GMT) Date: Sat, 10 Feb 2024 01:43:50 +0000 (GMT) From: "Maciej W. Rozycki" To: =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= , Bjorn Helgaas cc: Mika Westerberg , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] PCI: Correct error reporting with PCIe failed link retraining In-Reply-To: Message-ID: References: User-Agent: Alpine 2.21 (DEB 202 2017-01-01) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Only return successful completion status from `pcie_failed_link_retrain'=20 if retraining has actually been done, preventing excessive delays from=20 being triggered at call sites in a hope that communication will finally=20 be established with the downstream device where in fact nothing has been=20 done about the link in question that would justify such a hope. Fixes: a89c82249c37 ("PCI: Work around PCIe link training failures") Reported-by: Ilpo J=C3=A4rvinen Link: https://lore.kernel.org/r/aa2d1c4e-9961-d54a-00c7-ddf8e858a9b0@linux.= intel.com/ Signed-off-by: Maciej W. Rozycki Cc: stable@vger.kernel.org # v6.5+ Reviewed-by: Ilpo J=C3=A4rvinen --- drivers/pci/quirks.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) linux-pcie-failed-link-retrain-status-fix.diff Index: linux-macro/drivers/pci/quirks.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-macro.orig/drivers/pci/quirks.c +++ linux-macro/drivers/pci/quirks.c @@ -74,7 +74,8 @@ * firmware may have already arranged and lift it with ports that already * report their data link being up. * - * Return TRUE if the link has been successfully retrained, otherwise FALS= E. + * Return TRUE if the link has been successfully retrained, otherwise FALS= E, + * also when retraining was not needed in the first place. */ bool pcie_failed_link_retrain(struct pci_dev *dev) { @@ -83,10 +84,11 @@ bool pcie_failed_link_retrain(struct pci {} }; u16 lnksta, lnkctl2; + bool ret =3D false; =20 if (!pci_is_pcie(dev) || !pcie_downstream_port(dev) || !pcie_cap_has_lnkctl2(dev) || !dev->link_active_reporting) - return false; + return ret; =20 pcie_capability_read_word(dev, PCI_EXP_LNKCTL2, &lnkctl2); pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta); @@ -98,9 +100,10 @@ bool pcie_failed_link_retrain(struct pci lnkctl2 |=3D PCI_EXP_LNKCTL2_TLS_2_5GT; pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, lnkctl2); =20 - if (pcie_retrain_link(dev, false)) { + ret =3D pcie_retrain_link(dev, false) =3D=3D 0; + if (!ret) { pci_info(dev, "retraining failed\n"); - return false; + return ret; } =20 pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta); @@ -117,13 +120,14 @@ bool pcie_failed_link_retrain(struct pci lnkctl2 |=3D lnkcap & PCI_EXP_LNKCAP_SLS; pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, lnkctl2); =20 - if (pcie_retrain_link(dev, false)) { + ret =3D pcie_retrain_link(dev, false) =3D=3D 0; + if (!ret) { pci_info(dev, "retraining failed\n"); - return false; + return ret; } } =20 - return true; + return ret; } =20 static ktime_t fixup_debug_start(struct pci_dev *dev, From nobody Mon Feb 9 11:07:35 2026 Received: from angie.orcam.me.uk (angie.orcam.me.uk [78.133.224.34]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1999B5224; Sat, 10 Feb 2024 01:43:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.133.224.34 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707529440; cv=none; b=Gy7rXXf59dzj4UeAtxmC7Sqpz75rRUMJyDDvdEnZtMXn/BbClKyxG8TDPvGY6fMG3gTZ2tEetNt7iNWc7pyGkYDSA+Z+AfU0llY4y+O9vanCydohRU0UFOMHKuKSxosNOm9imSNY0PBZOT+E4L4N5dIZt9kXu9uP6h44TwdeR3E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707529440; c=relaxed/simple; bh=28h1Rh+hwi9ySwZ9U39BbdIl4KPwF0VAfeo/sYnViDs=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=u9n6ZQL9aAVzHahYFy0872XXFL1WVCCT3afFxheuzey3K0BN/H7b3WQFXwB2SpFQpiBFpcrx55z6ozqXKT63XF+T5ESa9nUNEvLDmlS3FQSpcHEgpNQbRLCTwAbvNCAMtCn7e0dnZDUpsAqyPe4c54abStbZ18NozSx1qMe3LVw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=orcam.me.uk; spf=none smtp.mailfrom=orcam.me.uk; arc=none smtp.client-ip=78.133.224.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=orcam.me.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=orcam.me.uk Received: by angie.orcam.me.uk (Postfix, from userid 500) id 9A6E09200B3; Sat, 10 Feb 2024 02:43:56 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by angie.orcam.me.uk (Postfix) with ESMTP id 9443B92009E; Sat, 10 Feb 2024 01:43:56 +0000 (GMT) Date: Sat, 10 Feb 2024 01:43:56 +0000 (GMT) From: "Maciej W. Rozycki" To: =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= , Bjorn Helgaas cc: Mika Westerberg , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] PCI: Use an error code with PCIe failed link retraining In-Reply-To: Message-ID: References: User-Agent: Alpine 2.21 (DEB 202 2017-01-01) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Given how the call place in `pcie_wait_for_link_delay' got structured=20 now, and that `pcie_retrain_link' returns a potentially useful error=20 code, convert `pcie_failed_link_retrain' to return an error code rather=20 than a boolean status, fixing handling at the call site mentioned. =20 Update the other call site accordingly. Fixes: 1abb47390350 ("Merge branch 'pci/enumeration'") Reported-by: Ilpo J=C3=A4rvinen Link: https://lore.kernel.org/r/aa2d1c4e-9961-d54a-00c7-ddf8e858a9b0@linux.= intel.com/ Signed-off-by: Maciej W. Rozycki Cc: stable@vger.kernel.org # v6.5+ Reviewed-by: Ilpo J=C3=A4rvinen --- drivers/pci/pci.c | 2 +- drivers/pci/pci.h | 6 +++--- drivers/pci/quirks.c | 14 +++++++------- 3 files changed, 11 insertions(+), 11 deletions(-) linux-pcie-failed-link-retrain-status-int.diff Index: linux-macro/drivers/pci/pci.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-macro.orig/drivers/pci/pci.c +++ linux-macro/drivers/pci/pci.c @@ -1263,7 +1263,7 @@ static int pci_dev_wait(struct pci_dev * if (delay > PCI_RESET_WAIT) { if (retrain) { retrain =3D false; - if (pcie_failed_link_retrain(bridge)) { + if (pcie_failed_link_retrain(bridge) =3D=3D 0) { delay =3D 1; continue; } Index: linux-macro/drivers/pci/pci.h =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-macro.orig/drivers/pci/pci.h +++ linux-macro/drivers/pci/pci.h @@ -540,7 +540,7 @@ void pci_acs_init(struct pci_dev *dev); int pci_dev_specific_acs_enabled(struct pci_dev *dev, u16 acs_flags); int pci_dev_specific_enable_acs(struct pci_dev *dev); int pci_dev_specific_disable_acs_redir(struct pci_dev *dev); -bool pcie_failed_link_retrain(struct pci_dev *dev); +int pcie_failed_link_retrain(struct pci_dev *dev); #else static inline int pci_dev_specific_acs_enabled(struct pci_dev *dev, u16 acs_flags) @@ -555,9 +555,9 @@ static inline int pci_dev_specific_disab { return -ENOTTY; } -static inline bool pcie_failed_link_retrain(struct pci_dev *dev) +static inline int pcie_failed_link_retrain(struct pci_dev *dev) { - return false; + return -ENOTTY; } #endif =20 Index: linux-macro/drivers/pci/quirks.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-macro.orig/drivers/pci/quirks.c +++ linux-macro/drivers/pci/quirks.c @@ -74,17 +74,17 @@ * firmware may have already arranged and lift it with ports that already * report their data link being up. * - * Return TRUE if the link has been successfully retrained, otherwise FALS= E, + * Return 0 if the link has been successfully retrained, otherwise an erro= r, * also when retraining was not needed in the first place. */ -bool pcie_failed_link_retrain(struct pci_dev *dev) +int pcie_failed_link_retrain(struct pci_dev *dev) { static const struct pci_device_id ids[] =3D { { PCI_VDEVICE(ASMEDIA, 0x2824) }, /* ASMedia ASM2824 */ {} }; u16 lnksta, lnkctl2; - bool ret =3D false; + int ret =3D -ENOTTY; =20 if (!pci_is_pcie(dev) || !pcie_downstream_port(dev) || !pcie_cap_has_lnkctl2(dev) || !dev->link_active_reporting) @@ -100,8 +100,8 @@ bool pcie_failed_link_retrain(struct pci lnkctl2 |=3D PCI_EXP_LNKCTL2_TLS_2_5GT; pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, lnkctl2); =20 - ret =3D pcie_retrain_link(dev, false) =3D=3D 0; - if (!ret) { + ret =3D pcie_retrain_link(dev, false); + if (ret) { pci_info(dev, "retraining failed\n"); return ret; } @@ -120,8 +120,8 @@ bool pcie_failed_link_retrain(struct pci lnkctl2 |=3D lnkcap & PCI_EXP_LNKCAP_SLS; pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, lnkctl2); =20 - ret =3D pcie_retrain_link(dev, false) =3D=3D 0; - if (!ret) { + ret =3D pcie_retrain_link(dev, false); + if (ret) { pci_info(dev, "retraining failed\n"); return ret; }