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")
Reported-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/aa2d1c4e-9961-d54a-00c7-ddf8e858a9b0@xxxxxxxxxxxxxxx/
Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxx>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v6.5+
---
No changes from v2.
Changes from v1 (superseding 1/2):
- Regenerate on top of 2/4.
- Reword the comment update for clarity.
- Go back to returning explicit FALSE rather than `ret' where it is known
that we failed.
---
drivers/pci/quirks.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
linux-pcie-failed-link-retrain-status-fix.diff
Index: linux-macro/drivers/pci/quirks.c
===================================================================
--- linux-macro.orig/drivers/pci/quirks.c
+++ linux-macro/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,
