6.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Maciej W. Rozycki macro@orcam.me.uk
commit 712e49c967064a3a7a5738c6f65ac540a3f6a1df upstream.
Only return successful completion status from pcie_failed_link_retrain() if retraining has actually been done, preventing excessive delays from being triggered at call sites in a hope that communication will finally be established with the downstream device where in fact nothing has been done about the link in question that would justify such a hope.
Fixes: a89c82249c37 ("PCI: Work around PCIe link training failures") Link: https://lore.kernel.org/r/alpine.DEB.2.21.2408091133260.61955@angie.orcam.me... Reported-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Link: https://lore.kernel.org/r/aa2d1c4e-9961-d54a-00c7-ddf8e858a9b0@linux.intel.c... Signed-off-by: Maciej W. Rozycki macro@orcam.me.uk Signed-off-by: Bjorn Helgaas bhelgaas@google.com Signed-off-by: Krzysztof Wilczyński kwilczynski@kernel.org Reviewed-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Cc: stable@vger.kernel.org # v6.5+ Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/pci/quirks.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
--- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -78,7 +78,8 @@ * again to remove any residual state, ignoring the result as it's supposed * to fail anyway. * - * Return TRUE if the link has been successfully retrained, otherwise FALSE. + * Return TRUE if the link has been successfully retrained. Return FALSE + * if retraining was not needed or we attempted a retrain and it failed. */ bool pcie_failed_link_retrain(struct pci_dev *dev) { @@ -87,6 +88,7 @@ bool pcie_failed_link_retrain(struct pci {} }; u16 lnksta, lnkctl2; + bool ret = false;
if (!pci_is_pcie(dev) || !pcie_downstream_port(dev) || !pcie_cap_has_lnkctl2(dev) || !dev->link_active_reporting) @@ -104,7 +106,8 @@ bool pcie_failed_link_retrain(struct pci lnkctl2 |= PCI_EXP_LNKCTL2_TLS_2_5GT; pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, lnkctl2);
- if (pcie_retrain_link(dev, false)) { + ret = pcie_retrain_link(dev, false) == 0; + if (!ret) { pci_info(dev, "retraining failed\n"); pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, oldlnkctl2); @@ -126,13 +129,14 @@ bool pcie_failed_link_retrain(struct pci lnkctl2 |= lnkcap & PCI_EXP_LNKCAP_SLS; pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, lnkctl2);
- if (pcie_retrain_link(dev, false)) { + ret = pcie_retrain_link(dev, false) == 0; + if (!ret) { pci_info(dev, "retraining failed\n"); return false; } }
- return true; + return ret; }
static ktime_t fixup_debug_start(struct pci_dev *dev,