If we use sysfs to disable L1 ASPM, then enable one L1 ASPM substate again, all other substates will also be enabled too: link# grep . * clkpm:1 l0s_aspm:1 l1_1_aspm:1 l1_1_pcipm:1 l1_2_aspm:1 l1_2_pcipm:1 l1_aspm:1 link# echo 0 > l1_aspm link# grep . * clkpm:1 l0s_aspm:1 l1_1_aspm:0 l1_1_pcipm:0 l1_2_aspm:0 l1_2_pcipm:0 l1_aspm:0 link# echo 1 > l1_2_aspm link# grep . * clkpm:1 l0s_aspm:1 l1_1_aspm:1 l1_1_pcipm:1 l1_2_aspm:1 l1_2_pcipm:1 l1_aspm:1 This is because disabled ASPM states weren't saved, so enable any of the substate will also enable others. So store the disabled ASPM states for consistency. Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> --- drivers/pci/pcie/aspm.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index ac0557a305af..2ea9fddadfad 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -658,6 +658,8 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) /* Setup initial capable state. Will be updated later */ link->aspm_capable = link->aspm_support; + link->aspm_disable = link->aspm_capable & ~link->aspm_default; + /* Get and check endpoint acceptable latencies */ list_for_each_entry(child, &linkbus->devices, bus_list) { u32 reg32, encoding; @@ -1226,11 +1228,15 @@ static ssize_t aspm_attr_store_common(struct device *dev, mutex_lock(&aspm_lock); if (state_enable) { - link->aspm_disable &= ~state; /* need to enable L1 for substates */ if (state & ASPM_STATE_L1SS) - link->aspm_disable &= ~ASPM_STATE_L1; + state |= ASPM_STATE_L1; + + link->aspm_disable &= ~state; } else { + if (state == ASPM_STATE_L1) + state |= ASPM_STATE_L1SS; + link->aspm_disable |= state; } -- 2.29.2