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Subject[PATCH v2 1/3] PCI/ASPM: Store disabled ASPM states
Date
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@canonical.com>
---
v2:
- Drop redundant change.

drivers/pci/pcie/aspm.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 013a47f587ce..30b1bc899026 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;
@@ -1231,6 +1233,9 @@ static ssize_t aspm_attr_store_common(struct device *dev,
if (state & ASPM_STATE_L1SS)
link->aspm_disable &= ~ASPM_STATE_L1;
} else {
+ if (state == ASPM_STATE_L1)
+ state |= ASPM_STATE_L1SS;
+
link->aspm_disable |= state;
}

--
2.32.0
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