| Message ID | 20250321163103.5145-1-ilpo.jarvinen@linux.intel.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [1/1] PCI/bwctrl: Fix link speed return type | expand |
On Fri, Mar 21, 2025 at 06:31:03PM +0200, Ilpo Järvinen wrote: > 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 synthetize 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). > > Fixes: de9a6c8d5dbf ("PCI/bwctrl: Add pcie_set_target_speed() to set PCIe Link Speed") > Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Applied to pci/bwctrl for v6.15, thanks! > --- > 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 0a5e7efbce2c..58ba8142c9a3 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); > } > > base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b > -- > 2.39.5 >
diff --git a/drivers/pci/pcie/bwctrl.c b/drivers/pci/pcie/bwctrl.c index 0a5e7efbce2c..58ba8142c9a3 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); }
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 synthetize 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). Fixes: de9a6c8d5dbf ("PCI/bwctrl: Add pcie_set_target_speed() to set PCIe Link Speed") Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> --- drivers/pci/pcie/bwctrl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b