Re: [PATCH] mt76: mt7921: fix possible resume failure

sean.wang
2021-12-07T17:22:15Z

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

>> 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.
>
>do we have a similar issue in mt7921s_resume()?

We don't have the same issue found in mt7921s_resume because the driver
guarantees all MCU commands (even in mt7921s_resume) always work in the active
state.

But we can have the same patch for mt7921s just to make code consistent with
mt7921e.

>
>>
>> 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
>>
>