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From:   Koba Ko <koba.ko@canonical.com>
Date:   Fri, 4 Jun 2021 17:08:51 +0800
Message-ID: <CAJB-X+U5VEeSNS4sF0DBxc-p0nxA6QLVVrORHsscZuY37rGJ7w@mail.gmail.com>
Subject: Re: [PATCH] r8169: introduce polling method for link change
To:     Heiner Kallweit <hkallweit1@gmail.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Fri, Jun 4, 2021 at 4:23 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
>
> On 04.06.2021 09:22, Koba Ko wrote:
> > On Thu, Jun 3, 2021 at 6:00 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
> >>
> >> On 03.06.2021 04:54, Koba Ko wrote:
> >>> For RTL8106E, it's a Fast-ethernet chip.
> >>> If ASPM is enabled, the link chang interrupt wouldn't be triggered
> >>> immediately and must wait a very long time to get link change interrupt.
> >>> Even the link change interrupt isn't triggered, the phy link is already
> >>> established.
> >>>
> >> At first please provide a full dmesg log and output of lspci -vv.
> >> Do you have the firmware for the NIC loaded? Please provide "ethtool -i <if>"
> >> output.
> >
> > please get the logs from here,
> > https://bugzilla.kernel.org/show_bug.cgi?id=213165
> >
> >> Does the issue affect link-down and/or link-up detection?
> >> Do you have runtime pm enabled? Then, after 10s of link-down NIC goes to
> >> D3hot and link-up detection triggers a PME.
> >
> > Issue affect link-up.
> > yes, pm runtime is enabled, but rtl8106e always stays D0 even if the
> > cable isn't present.
> >
> Then runtime pm doesn't seem to be set to "auto". Else 10s after link loss
> the chip runtime-suspends and is set to D3hot.

I will check this.

>
> >>
> >>> Introduce a polling method to watch the status of phy link and disable
> >>> the link change interrupt.
> >>> Also add a quirk for those realtek devices have the same issue.
> >>>
> >> Which are the affected chip versions? Did you check with Realtek?
> >> Your patch switches to polling for all Fast Ethernet versions,
> >> and that's not what we want.
> >
> > I don't know the exact version, only the chip name 806e(pci device id 0x8165).
> > ok, Im asking Realtek to help how to identify the chip issue is observed.
> >
> At least your Bugzilla report refers to VER_39. PCI device id 0x8136 is shared
> by all fast ethernet chip versions.
> Do you know other affected chip versions apart from VER_39 ?
>
> In the Bugzilla report you also write the issue occurs with GBit-capable
> link partners. This sounds more like an aneg problem.
> The issue doesn't occur with fast ethernet link partners?

Issue wouldn't be observed when the link-partner has only FE capability.

>
> Your bug report also includes a patch that disables L1_1 only.
> Not sure how this is related because the chip version we speak about
> here doesn't support L1 sub-states.

I have tried to enable L0s, L1 and don't disable L1 substate,
but still get the issue that interrupt can't be fired immediately but
the Link status is up.

>
> >>
> >> My suspicion would be that something is system-dependent. Else I think
> >> we would have seen such a report before.
> > On the mainline, the aspm is disable, so you may not observe this.
> > If you enable ASPM and must wait CHIP go to power-saving mode, then
> > you can observe the issue.
> >>
>
> So what you're saying is that mainline is fine and your problem is with
> a downstream kernel with re-enabled ASPM? So there's nothing broken in
> mainline? In mainline you have the option to re-enable ASPM states
> individually via sysfs (link subdir at pci device).

If enable L1_1 on the mainline, the issue could be observed too.

Thanks
>
> >>> Signed-off-by: Koba Ko <koba.ko@canonical.com>
> >>> ---
> >>>  drivers/net/ethernet/realtek/r8169.h      |   2 +
> >>>  drivers/net/ethernet/realtek/r8169_main.c | 112 ++++++++++++++++++----
> >>>  2 files changed, 98 insertions(+), 16 deletions(-)
> >>>
> >>> diff --git a/drivers/net/ethernet/realtek/r8169.h b/drivers/net/ethernet/realtek/r8169.h
> >>> index 2728df46ec41..a8c71adb1b57 100644
> >>> --- a/drivers/net/ethernet/realtek/r8169.h
> >>> +++ b/drivers/net/ethernet/realtek/r8169.h
> >>> @@ -11,6 +11,8 @@
> >>>  #include <linux/types.h>
> >>>  #include <linux/phy.h>
> >>>
> >>> +#define RTL8169_LINK_TIMEOUT (1 * HZ)
> >>> +
> >>>  enum mac_version {
> >>>       /* support for ancient RTL_GIGA_MAC_VER_01 has been removed */
> >>>       RTL_GIGA_MAC_VER_02,
> >>> diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
> >>> index 2c89cde7da1e..70aacc83d641 100644
> >>> --- a/drivers/net/ethernet/realtek/r8169_main.c
> >>> +++ b/drivers/net/ethernet/realtek/r8169_main.c
> >>> @@ -178,6 +178,11 @@ static const struct pci_device_id rtl8169_pci_tbl[] = {
> >>>
> >>>  MODULE_DEVICE_TABLE(pci, rtl8169_pci_tbl);
> >>>
> >>> +static const struct pci_device_id rtl8169_linkChg_polling_enabled[] = {
> >>> +     { PCI_VDEVICE(REALTEK, 0x8136), RTL_CFG_NO_GBIT },
> >>> +     { 0 }
> >>> +};
> >>> +
> >>
> >> This doesn't seem to be used.
> >>
> >>>  enum rtl_registers {
> >>>       MAC0            = 0,    /* Ethernet hardware address. */
> >>>       MAC4            = 4,
> >>> @@ -618,6 +623,7 @@ struct rtl8169_private {
> >>>       u16 cp_cmd;
> >>>       u32 irq_mask;
> >>>       struct clk *clk;
> >>> +     struct timer_list link_timer;
> >>>
> >>>       struct {
> >>>               DECLARE_BITMAP(flags, RTL_FLAG_MAX);
> >>> @@ -1179,6 +1185,16 @@ static void rtl8168ep_stop_cmac(struct rtl8169_private *tp)
> >>>       RTL_W8(tp, IBCR0, RTL_R8(tp, IBCR0) & ~0x01);
> >>>  }
> >>>
> >>> +static int rtl_link_chng_polling_quirk(struct rtl8169_private *tp)
> >>> +{
> >>> +     struct pci_dev *pdev = tp->pci_dev;
> >>> +
> >>> +     if (pdev->vendor == 0x10ec && pdev->device == 0x8136 && !tp->supports_gmii)
> >>> +             return 1;
> >>> +
> >>> +     return 0;
> >>> +}
> >>> +
> >>>  static void rtl8168dp_driver_start(struct rtl8169_private *tp)
> >>>  {
> >>>       r8168dp_oob_notify(tp, OOB_CMD_DRIVER_START);
> >>> @@ -4608,6 +4624,75 @@ static void rtl_task(struct work_struct *work)
> >>>       rtnl_unlock();
> >>>  }
> >>>
> >>> +static void r8169_phylink_handler(struct net_device *ndev)
> >>> +{
> >>> +     struct rtl8169_private *tp = netdev_priv(ndev);
> >>> +
> >>> +     if (netif_carrier_ok(ndev)) {
> >>> +             rtl_link_chg_patch(tp);
> >>> +             pm_request_resume(&tp->pci_dev->dev);
> >>> +     } else {
> >>> +             pm_runtime_idle(&tp->pci_dev->dev);
> >>> +     }
> >>> +
> >>> +     if (net_ratelimit())
> >>> +             phy_print_status(tp->phydev);
> >>> +}
> >>> +
> >>> +static unsigned int
> >>> +rtl8169_xmii_link_ok(struct net_device *dev)
> >>> +{
> >>> +     struct rtl8169_private *tp = netdev_priv(dev);
> >>> +     unsigned int retval;
> >>> +
> >>> +     retval = (RTL_R8(tp, PHYstatus) & LinkStatus) ? 1 : 0;
> >>> +
> >>> +     return retval;
> >>> +}
> >>> +
> >>> +static void
> >>> +rtl8169_check_link_status(struct net_device *dev)
> >>> +{
> >>> +     struct rtl8169_private *tp = netdev_priv(dev);
> >>> +     int link_status_on;
> >>> +
> >>> +     link_status_on = rtl8169_xmii_link_ok(dev);
> >>> +
> >>> +     if (netif_carrier_ok(dev) == link_status_on)
> >>> +             return;
> >>> +
> >>> +     phy_mac_interrupt(tp->phydev);
> >>> +
> >>> +     r8169_phylink_handler (dev);
> >>> +}
> >>> +
> >>> +static void rtl8169_link_timer(struct timer_list *t)
> >>> +{
> >>> +     struct rtl8169_private *tp = from_timer(tp, t, link_timer);
> >>> +     struct net_device *dev = tp->dev;
> >>> +     struct timer_list *timer = t;
> >>> +     unsigned long flags;
> >>
> >> flags isn't used and triggers a compiler warning. Did you even
> >> compile-test your patch?
> >>
> >>> +
> >>> +     rtl8169_check_link_status(dev);
> >>> +
> >>> +     if (timer_pending(&tp->link_timer))
> >>> +             return;
> >>> +
> >>> +     mod_timer(timer, jiffies + RTL8169_LINK_TIMEOUT);
> >>> +}
> >>> +
> >>> +static inline void rtl8169_delete_link_timer(struct net_device *dev, struct timer_list *timer)
> >>> +{
> >>> +     del_timer_sync(timer);
> >>> +}
> >>> +
> >>> +static inline void rtl8169_request_link_timer(struct net_device *dev)
> >>> +{
> >>> +     struct rtl8169_private *tp = netdev_priv(dev);
> >>> +
> >>> +     timer_setup(&tp->link_timer, rtl8169_link_timer, TIMER_INIT_FLAGS);
> >>> +}
> >>> +
> >>>  static int rtl8169_poll(struct napi_struct *napi, int budget)
> >>>  {
> >>>       struct rtl8169_private *tp = container_of(napi, struct rtl8169_private, napi);
> >>> @@ -4624,21 +4709,6 @@ static int rtl8169_poll(struct napi_struct *napi, int budget)
> >>>       return work_done;
> >>>  }
> >>>
> >>> -static void r8169_phylink_handler(struct net_device *ndev)
> >>> -{
> >>> -     struct rtl8169_private *tp = netdev_priv(ndev);
> >>> -
> >>> -     if (netif_carrier_ok(ndev)) {
> >>> -             rtl_link_chg_patch(tp);
> >>> -             pm_request_resume(&tp->pci_dev->dev);
> >>> -     } else {
> >>> -             pm_runtime_idle(&tp->pci_dev->dev);
> >>> -     }
> >>> -
> >>> -     if (net_ratelimit())
> >>> -             phy_print_status(tp->phydev);
> >>> -}
> >>> -
> >>>  static int r8169_phy_connect(struct rtl8169_private *tp)
> >>>  {
> >>>       struct phy_device *phydev = tp->phydev;
> >>> @@ -4769,6 +4839,10 @@ static int rtl_open(struct net_device *dev)
> >>>               goto err_free_irq;
> >>>
> >>>       rtl8169_up(tp);
> >>> +
> >>> +     if (rtl_link_chng_polling_quirk(tp))
> >>> +             mod_timer(&tp->link_timer, jiffies + RTL8169_LINK_TIMEOUT);
> >>> +
> >>>       rtl8169_init_counter_offsets(tp);
> >>>       netif_start_queue(dev);
> >>>  out:
> >>> @@ -4991,7 +5065,10 @@ static const struct net_device_ops rtl_netdev_ops = {
> >>>
> >>>  static void rtl_set_irq_mask(struct rtl8169_private *tp)
> >>>  {
> >>> -     tp->irq_mask = RxOK | RxErr | TxOK | TxErr | LinkChg;
> >>> +     tp->irq_mask = RxOK | RxErr | TxOK | TxErr;
> >>> +
> >>> +     if (!rtl_link_chng_polling_quirk(tp))
> >>> +             tp->irq_mask |= LinkChg;
> >>>
> >>>       if (tp->mac_version <= RTL_GIGA_MAC_VER_06)
> >>>               tp->irq_mask |= SYSErr | RxOverflow | RxFIFOOver;
> >>> @@ -5436,6 +5513,9 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
> >>>       if (pci_dev_run_wake(pdev))
> >>>               pm_runtime_put_sync(&pdev->dev);
> >>>
> >>> +     if (rtl_link_chng_polling_quirk(tp))
> >>> +             rtl8169_request_link_timer(dev);
> >>> +
> >>>       return 0;
> >>>  }
> >>>
> >>>
> >>
> >> All this isn't needed. If you want to switch to link status polling,
> >> why don't you simply let phylib do it? PHY_MAC_INTERRUPT -> PHY_POLL
> >
> > Thanks for suggestions, I tried to use PHY_POLL, it could do the same
> > thing that I did.
> >
> >> Your timer-based code most likely would have problems if runtime pm
> >> is enabled. Then you try to read the link status whilst NIC is in
> >> D3hot.
>