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

Lorenzo Bianconi
2021-12-07T20:08:14Z

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> 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.

ack, agree.

Regards,
Lorenzo

>
> >
> >>
> >> 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
> >>
> >
>

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