So far we may see an unexpected behavior regard L1 sub-states.
Following scenario:
Write 0 to "l1_aspm" to disable L1
Write 1 to "l1_1_aspm" to enable L1.1
Intention of step 1 is to implicitly disable also L1.1 and L1.2.
However after step 2 L1.2 is unexpectedly enabled.
Fix this by explicitly disabling L1 sub-states when disabling L1.
Fixes: 72ea91afbfb0 ("PCI/ASPM: Add sysfs attributes for controlling ASPM link states")
Link: https://lore.kernel.org/linux-pci/20231002151452.GA560499@bhelgaas/
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
---
Splitted-out part of original patch according to linked discussion.
---
drivers/pci/pcie/aspm.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 530c3bb5708c..fc18e42f0a6e 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -1248,6 +1248,8 @@ static ssize_t aspm_attr_store_common(struct device *dev,
link->aspm_disable &= ~ASPM_STATE_L1;
} else {
link->aspm_disable |= state;
+ if (state & ASPM_STATE_L1)
+ link->aspm_disable |= ASPM_STATE_L1SS;
}
pcie_config_aspm_link(link, policy_to_aspm_state(link));
--
2.42.0
