From:   <sean.wang@mediatek.com>
To:     <nbd@nbd.name>, <lorenzo.bianconi@redhat.com>
CC:     <sean.wang@mediatek.com>, <Soul.Huang@mediatek.com>,
        <YN.Chen@mediatek.com>, <Leon.Yen@mediatek.com>,
        <Eric-SY.Chang@mediatek.com>, <Mark-YW.Chen@mediatek.com>,
        <Deren.Wu@mediatek.com>, <km.lin@mediatek.com>,
        <robin.chiu@mediatek.com>, <Eddie.Chen@mediatek.com>,
        <ch.yeh@mediatek.com>, <posh.sun@mediatek.com>,
        <ted.huang@mediatek.com>, <Eric.Liang@mediatek.com>,
        <Stella.Chang@mediatek.com>, <Tom.Chou@mediatek.com>,
        <steve.lee@mediatek.com>, <jsiuda@google.com>,
        <frankgor@google.com>, <jemele@google.com>,
        <abhishekpandit@google.com>, <shawnku@google.com>,
        <linux-wireless@vger.kernel.org>,
        <linux-mediatek@lists.infradead.org>
Subject: [PATCH] mt76: mt7921: fix possible resume failure
Date:   Tue, 7 Dec 2021 10:35:07 +0800
Message-ID: <ff1e35dcaa0a56c04339bba2ebd2c68bf815919c.1638844068.git.objelf@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

From: Sean Wang <sean.wang@mediatek.com>

Fix the possible resume failure due to mt76_connac_mcu_set_hif_suspend
timeout.

That is because clearing the flag pm->suspended too early opened up a race
window, where mt7921_poll_tx/rx scheduled a ps_work to put the device in
doze mode, that is unexpected for the device is being resumed from the
suspend state and would make the remaining MCU comamnds in resume handler
failed to execute.

Fixes: ffa1bf97425b ("mt76: mt7921: introduce PM support")
Co-developed-by: YN Chen <YN.Chen@mediatek.com>
Signed-off-by: YN Chen <YN.Chen@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
---
 drivers/net/wireless/mediatek/mt76/mt7921/pci.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/pci.c b/drivers/net/wireless/mediatek/mt76/mt7921/pci.c
index 5635de3c80b1..21a48f02ab60 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/pci.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/pci.c
@@ -315,7 +315,6 @@ static int mt7921_pci_resume(struct pci_dev *pdev)
 	struct mt76_connac_pm *pm = &dev->pm;
 	int i, err;
 
-	pm->suspended = false;
 	err = pci_set_power_state(pdev, PCI_D0);
 	if (err)
 		return err;
@@ -353,7 +352,11 @@ static int mt7921_pci_resume(struct pci_dev *pdev)
 	if (!pm->ds_enable)
 		mt76_connac_mcu_set_deep_sleep(&dev->mt76, false);
 
-	return mt76_connac_mcu_set_hif_suspend(mdev, false);
+	err = mt76_connac_mcu_set_hif_suspend(mdev, false);
+
+	pm->suspended = false;
+
+	return err;
 }
 #endif /* CONFIG_PM */
 
-- 
2.25.1