[PATCH v2 2/2] PCI: reread the Link Control 2 Register before using

Jiwei Sun
2025-01-15T13:42:39Z

From: Jiwei Sun <sunjw10@lenovo.com>

Since commit de9a6c8d5dbf ("PCI/bwctrl: Add pcie_set_target_speed() to set
PCIe Link Speed"), the local variable "lnkctl2" is not changed after
reading from PCI_EXP_LNKCTL2 in the pcie_failed_link_retrain(). It might
cause that the removing 2.5GT/s downstream link speed restriction codes
are not executed.

Reread the Link Control 2 Register before using.

Fixes: de9a6c8d5dbf ("PCI/bwctrl: Add pcie_set_target_speed() to set PCIe Link Speed")
Suggested-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Jiwei Sun <sunjw10@lenovo.com>
---
drivers/pci/quirks.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 76f4df75b08a..02d2e16672a8 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -123,6 +123,7 @@ int pcie_failed_link_retrain(struct pci_dev *dev)
return ret;
}

+ pcie_capability_read_word(dev, PCI_EXP_LNKCTL2, &lnkctl2);
pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta);
}

--
2.34.1