PCI: Correct error reporting with PCIe failed link retraining

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: a89c82249c ("PCI: Work around PCIe link training failures")
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2408091133260.61955@angie.orcam.me.uk
Reported-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/aa2d1c4e-9961-d54a-00c7-ddf8e858a9b0@linux.intel.com/
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+
This commit is contained in:
Maciej W. Rozycki 2024-08-09 14:24:56 +01:00 committed by Krzysztof Wilczyński
parent f68dea1340
commit 712e49c967
No known key found for this signature in database
GPG Key ID: 7C64768D3DE334E7

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@ -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_dev *dev)
{}
};
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_dev *dev)
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_dev *dev)
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,