linux-kernel - [PATCH 1/2] PCI/ASPM: Store disabled ASPM states

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Message-Id: <20201208082534.2460215-1-kai.heng.feng@canonical.com>
Date:   Tue,  8 Dec 2020 16:25:33 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     bhelgaas@...gle.com
Cc:     hkallweit1@...il.com, Kai-Heng Feng <kai.heng.feng@...onical.com>,
        "Saheed O. Bolarinwa" <refactormyself@...il.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Chris Packham <chris.packham@...iedtelesis.co.nz>,
        Xiongfeng Wang <wangxiongfeng2@...wei.com>,
        Yicong Yang <yangyicong@...ilicon.com>,
        linux-pci@...r.kernel.org (open list:PCI SUBSYSTEM),
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH 1/2] PCI/ASPM: Store disabled ASPM states

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@...onical.com>
---
 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