PCI/ASPM: Fix L1 substate handling in aspm_attr_store_common()

aspm_attr_store_common(), which handles sysfs control of ASPM, has the same
problem as fb097dc ("PCI/ASPM: Disable only ASPM_STATE_L1 when driver
disables L1"): disabling L1 adds only ASPM_L1 (but not any of the L1.x
substates) to the "aspm_disable" mask.

Enabling one substate, e.g., L1.1, via sysfs removes ASPM_L1 from the
disable mask.  Since disabling L1 via sysfs doesn't add any of the
substates to the disable mask, enabling L1.1 actually enables *all* the
substates.

In this scenario:

  - Write 0 to "l1_aspm" to disable L1
  - Write 1 to "l1_1_aspm" to enable L1.1

the intention is to disable L1 and all L1.x substates, then enable just
L1.1, but in fact, *all* L1.x substates are enabled.

Fix this by explicitly disabling all the L1.x substates when disabling L1.

Fixes: 72ea91a ("PCI/ASPM: Add sysfs attributes for controlling ASPM link states")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Heiner Kallweit <[email protected]>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <[email protected]>
Cc: [email protected]

Author: hkallweit

drivers/pci/pcie/aspm.c

@@ -1255,6 +1255,8 @@ 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));