netdev - RE: [PATCH net] r8169: fix rtl8125b dmar pte write access not set error

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Message-ID: <c214fed3af19464c823a5294f531eaea@realtek.com>
Date:   Mon, 17 Oct 2022 17:23:11 +0000
From:   Hau <hau@...ltek.com>
To:     Heiner Kallweit <hkallweit1@...il.com>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        nic_swsd <nic_swsd@...ltek.com>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "grundler@...omium.org" <grundler@...omium.org>
Subject: RE: [PATCH net] r8169: fix rtl8125b dmar pte write access not set error

> On 13.10.2022 08:04, Hau wrote:
> >> On 12.10.2022 09:59, Hau wrote:
> >>>>
> >>>> On 04.10.2022 10:10, Chunhao Lin wrote:
> >>>>> When close device, rx will be enabled if wol is enabeld. When open
> >>>>> device it will cause rx to dma to wrong address after pci_set_master().
> >>>>>
> >>>>> In this patch, driver will disable tx/rx when close device. If wol
> >>>>> is eanbled only enable rx filter and disable rxdv_gate to let
> >>>>> hardware can receive packet to fifo but not to dma it.
> >>>>>
> >>>>> Fixes: 120068481405 ("r8169: fix failing WoL")
> >>>>> Signed-off-by: Chunhao Lin <hau@...ltek.com>
> >>>>> ---
> >>>>>  drivers/net/ethernet/realtek/r8169_main.c | 14 +++++++-------
> >>>>>  1 file changed, 7 insertions(+), 7 deletions(-)
> >>>>>
> >>>>> diff --git a/drivers/net/ethernet/realtek/r8169_main.c
> >>>>> b/drivers/net/ethernet/realtek/r8169_main.c
> >>>>> index 1b7fdb4f056b..c09cfbe1d3f0 100644
> >>>>> --- a/drivers/net/ethernet/realtek/r8169_main.c
> >>>>> +++ b/drivers/net/ethernet/realtek/r8169_main.c
> >>>>> @@ -2239,6 +2239,9 @@ static void rtl_wol_enable_rx(struct
> >>>> rtl8169_private *tp)
> >>>>>  	if (tp->mac_version >= RTL_GIGA_MAC_VER_25)
> >>>>>  		RTL_W32(tp, RxConfig, RTL_R32(tp, RxConfig) |
> >>>>>  			AcceptBroadcast | AcceptMulticast | AcceptMyPhys);
> >>>>> +
> >>>>> +	if (tp->mac_version >= RTL_GIGA_MAC_VER_40)
> >>>>> +		RTL_W32(tp, MISC, RTL_R32(tp, MISC) &
> ~RXDV_GATED_EN);
> >>>>
> >>>> Is this correct anyway? Supposedly you want to set this bit to disable
> DMA.
> >>>>
> >>> If wol is enabled, driver need to disable hardware rxdv_gate for
> >>> receiving
> >> packets.
> >>>
> >> OK, I see. But why disable it here? I see no scenario where rxdv_gate
> >> would be enabled when we get here.
> >>
> > rxdv_gate will be enabled in rtl8169_cleanup(). When suspend or close
> > and wol is enabled driver will call rtl8169_down() -> rtl8169_cleanup()->
> rtl_prepare_power_down()-> rtl_wol_enable_rx().
> > So disabled rxdv_gate in rtl_wol_enable_rx() for receiving packets.
> >
> rtl8169_cleanup() skips the call to rtl_enable_rxdvgate() when being called
> from
> rtl8169_down() and wol is enabled. This means rxdv gate is still disabled.
> 
Yes, it will keep rxdv_gate disable. But it will also keep tx/rx on.  If OS have an  unexpected
reboot hardware  may dma to invalid memory address. If possible I prefer to keep
tx/rx off when exit driver control.  

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