6.13-stable review patch. If anyone has any objections, please let me know.
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From: Ilpo Järvinen ilpo.jarvinen@linux.intel.com
[ Upstream commit 026e4bffb0af9632f5a0bbf8d594f2aace44cf07 ]
pcie_bwctrl_select_speed() should take __fls() of the speed bit, not return it as a raw value. Instead of directly returning 2.5GT/s speed bit, simply assign the fallback speed (2.5GT/s) into supported_speeds variable to share the normal return path that calls pcie_supported_speeds2target_speed() to calculate __fls().
This code path is not very likely to execute because pcie_get_supported_speeds() should provide valid ->supported_speeds but a spec violating device could fail to synthesize any speed in pcie_get_supported_speeds(). It could also happen in case the supported_speeds intersection is empty (also a violation of the current PCIe specs).
Link: https://lore.kernel.org/r/20250321163103.5145-1-ilpo.jarvinen@linux.intel.co... Fixes: de9a6c8d5dbf ("PCI/bwctrl: Add pcie_set_target_speed() to set PCIe Link Speed") Signed-off-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/pcie/bwctrl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/pcie/bwctrl.c b/drivers/pci/pcie/bwctrl.c index 0a5e7efbce2cc..58ba8142c9a31 100644 --- a/drivers/pci/pcie/bwctrl.c +++ b/drivers/pci/pcie/bwctrl.c @@ -113,7 +113,7 @@ static u16 pcie_bwctrl_select_speed(struct pci_dev *port, enum pci_bus_speed spe up_read(&pci_bus_sem); } if (!supported_speeds) - return PCI_EXP_LNKCAP2_SLS_2_5GB; + supported_speeds = PCI_EXP_LNKCAP2_SLS_2_5GB;
return pcie_supported_speeds2target_speed(supported_speeds & desired_speeds); }