netdev - Re: [PATCH v2 2/2] r8169: Enable ASPM for selected NICs

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Date:   Sat, 14 Aug 2021 13:23:09 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Kai-Heng Feng <kai.heng.feng@...onical.com>
Cc:     nic_swsd <nic_swsd@...ltek.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        "open list:8169 10/100/1000 GIGABIT ETHERNET DRIVER" 
        <netdev@...r.kernel.org>, open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/2] r8169: Enable ASPM for selected NICs

On 13.08.2021 12:11, Kai-Heng Feng wrote:
> On Fri, Aug 13, 2021 at 3:39 AM Heiner Kallweit <hkallweit1@...il.com> wrote:
>>
>> On 12.08.2021 17:53, Kai-Heng Feng wrote:
>>> The latest vendor driver enables ASPM for more recent r8168 NICs, do the
>>> same here to match the behavior.
>>>
>>> In addition, pci_disable_link_state() is only used for RTL8168D/8111D in
>>> vendor driver, also match that.
>>>
>>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
>>> ---
>>> v2:
>>>  - No change
>>>
>>>  drivers/net/ethernet/realtek/r8169_main.c | 34 +++++++++++++++++------
>>>  1 file changed, 26 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
>>> index 7ab2e841dc69..caa29e72a21a 100644
>>> --- a/drivers/net/ethernet/realtek/r8169_main.c
>>> +++ b/drivers/net/ethernet/realtek/r8169_main.c
>>> @@ -623,7 +623,7 @@ struct rtl8169_private {
>>>       } wk;
>>>
>>>       unsigned supports_gmii:1;
>>> -     unsigned aspm_manageable:1;
>>> +     unsigned aspm_supported:1;
>>>       unsigned aspm_enabled:1;
>>>       struct delayed_work aspm_toggle;
>>>       struct mutex aspm_mutex;
>>> @@ -2667,8 +2667,11 @@ static void rtl_pcie_state_l2l3_disable(struct rtl8169_private *tp)
>>>
>>>  static void rtl_hw_aspm_clkreq_enable(struct rtl8169_private *tp, bool enable)
>>>  {
>>> +     if (!tp->aspm_supported)
>>> +             return;
>>> +
>>>       /* Don't enable ASPM in the chip if OS can't control ASPM */
>>> -     if (enable && tp->aspm_manageable) {
>>> +     if (enable) {
>>>               RTL_W8(tp, Config5, RTL_R8(tp, Config5) | ASPM_en);
>>>               RTL_W8(tp, Config2, RTL_R8(tp, Config2) | ClkReqEn);
>>>       } else {
>>> @@ -5284,6 +5287,21 @@ static void rtl_init_mac_address(struct rtl8169_private *tp)
>>>       rtl_rar_set(tp, mac_addr);
>>>  }
>>>
>>> +static int rtl_hw_aspm_supported(struct rtl8169_private *tp)
>>> +{
>>> +     switch (tp->mac_version) {
>>> +     case RTL_GIGA_MAC_VER_32 ... RTL_GIGA_MAC_VER_36:
>>> +     case RTL_GIGA_MAC_VER_38:
>>> +     case RTL_GIGA_MAC_VER_40 ... RTL_GIGA_MAC_VER_42:
>>> +     case RTL_GIGA_MAC_VER_44 ... RTL_GIGA_MAC_VER_46:
>>> +     case RTL_GIGA_MAC_VER_49 ... RTL_GIGA_MAC_VER_63:
>>
>> This shouldn't be needed because ASPM support is announced the
>> standard PCI way. Max a blacklist should be needed if there are
>> chip versions that announce ASPM support whilst in reality they
>> do not support it (or support is completely broken).
> 
> So can we also remove aspm_manageable since blacklist will be used?
> 
That's independent. What I mean is replace the whitelist with auto-
detected ASPM support and blacklist just the ones that are where
ASPM is completely unusable.
Retrieving the info about ASPM support may need a smll PCI core
extension. We need something similar to pcie_aspm_enabled(),
just exposing link->aspm_support. link->aspm_enabled may change
at runtime (sysfs link attributes).

> Kai-Heng
> 
>>
>>> +             return 1;
>>> +
>>> +     default:
>>> +             return 0;
>>> +     }
>>> +}
>>> +
>>>  static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
>>>  {
>>>       struct rtl8169_private *tp;
>>> @@ -5315,12 +5333,12 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
>>>       if (rc)
>>>               return rc;
>>>
>>> -     /* Disable ASPM completely as that cause random device stop working
>>> -      * problems as well as full system hangs for some PCIe devices users.
>>> -      */
>>> -     rc = pci_disable_link_state(pdev, PCIE_LINK_STATE_L0S |
>>> -                                       PCIE_LINK_STATE_L1);
>>> -     tp->aspm_manageable = !rc;
>>> +     if (tp->mac_version == RTL_GIGA_MAC_VER_25)
>>> +             pci_disable_link_state(pdev, PCIE_LINK_STATE_L0S |
>>> +                                    PCIE_LINK_STATE_L1 |
>>> +                                    PCIE_LINK_STATE_CLKPM);
>>> +
>>> +     tp->aspm_supported = rtl_hw_aspm_supported(tp);
>>>
>>>       /* enable device (incl. PCI PM wakeup and hotplug setup) */
>>>       rc = pcim_enable_device(pdev);
>>>
>>