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From: Kai-Heng Feng <kai.heng.feng@canonical.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Heiner Kallweit <hkallweit1@gmail.com>,
	nic_swsd <nic_swsd@realtek.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	David Miller <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Anthony Wong <anthony.wong@canonical.com>,
	Linux Netdev List <netdev@vger.kernel.org>,
	Linux PCI <linux-pci@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] [PATCH net-next v5 2/3] r8169: Use PCIe ASPM status for NIC ASPM enablement
Date: Fri, 1 Oct 2021 12:32:18 +0800	[thread overview]
Message-ID: <CAAd53p60Vjme9=zmVCF3WOt9iiqkZ6gprABDh1VSQyyKZbGkdw@mail.gmail.com> (raw)
In-Reply-To: <20210917152612.GA1717817@bjorn-Precision-5520>

On Fri, Sep 17, 2021 at 11:26 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> On Fri, Sep 17, 2021 at 12:09:08PM +0800, Kai-Heng Feng wrote:
> > On Fri, Sep 17, 2021 at 1:07 AM Bjorn Helgaas <helgaas@kernel.org> wrote:
> > > On Thu, Sep 16, 2021 at 11:44:16PM +0800, Kai-Heng Feng wrote:
> > > > Because ASPM control may not be granted by BIOS while ASPM is enabled,
> > > > and ASPM can be enabled via sysfs, so use pcie_aspm_enabled() directly
> > > > to check current ASPM enable status.
> > > >
> > > > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> > > > ---
> > > > v5:
> > > >  - New patch.
> > > >
> > > >  drivers/net/ethernet/realtek/r8169_main.c | 13 ++++++++-----
> > > >  1 file changed, 8 insertions(+), 5 deletions(-)
> > > >
> > > > diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
> > > > index 0199914440abc..6f1a9bec40c05 100644
> > > > --- a/drivers/net/ethernet/realtek/r8169_main.c
> > > > +++ b/drivers/net/ethernet/realtek/r8169_main.c
> > > > @@ -622,7 +622,6 @@ struct rtl8169_private {
> > > >       } wk;
> > > >
> > > >       unsigned supports_gmii:1;
> > > > -     unsigned aspm_manageable:1;
> > > >       dma_addr_t counters_phys_addr;
> > > >       struct rtl8169_counters *counters;
> > > >       struct rtl8169_tc_offsets tc_offset;
> > > > @@ -2664,8 +2663,13 @@ static void rtl_enable_exit_l1(struct rtl8169_private *tp)
> > > >
> > > >  static void rtl_hw_aspm_clkreq_enable(struct rtl8169_private *tp, bool enable)
> > > >  {
> > > > -     /* Don't enable ASPM in the chip if OS can't control ASPM */
> > > > -     if (enable && tp->aspm_manageable) {
> > > > +     struct pci_dev *pdev = tp->pci_dev;
> > > > +
> > > > +     /* Don't enable ASPM in the chip if PCIe ASPM isn't enabled */
> > > > +     if (!pcie_aspm_enabled(pdev) && enable)
> > > > +             return;
> > >
> > > What happens when the user enables or disables ASPM via sysfs (see
> > > https://git.kernel.org/linus/72ea91afbfb0)?
> > >
> > > The driver is not going to know about that change.
> >
> > So it's still better to fold this patch into next one? So the periodic
> > delayed_work can toggle ASPM accordingly.
>
> No, my point is that the user can enable/disable ASPM via sysfs, and
> the driver will not know anything about it.  There's no callback that
> tells the driver when this happens.
>
> My question is whether this code works when that happens.  I doubt it
> works, because if ASPM is not enabled at this moment, you return
> without doing enabling ASPM in the chip below.
>
> If the user subsequently enables ASPM via sysfs, the chip setup below
> will not be done.
>
> If there's chip-specific setup to make ASPM work, I think the
> chip-specific part needs to be done unconditionally.

So it's either adding a callback to notify driver about ASPM change,
or doing chip-specific ASPM unconditionally.
Which one do you prefer?

Kai-Heng

>
> > > > +     if (enable) {
> > > >               RTL_W8(tp, Config5, RTL_R8(tp, Config5) | ASPM_en);
> > > >               RTL_W8(tp, Config2, RTL_R8(tp, Config2) | ClkReqEn);
> > > >       } else {
> > > > @@ -5272,8 +5276,7 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
> > > >       /* Disable ASPM L1 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_L1);
> > > > -     tp->aspm_manageable = !rc;
> > > > +     pci_disable_link_state(pdev, PCIE_LINK_STATE_L1);
> > > >
> > > >       /* enable device (incl. PCI PM wakeup and hotplug setup) */
> > > >       rc = pcim_enable_device(pdev);
> > > > --
> > > > 2.32.0
> > > >

  reply	other threads:[~2021-10-01  4:32 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-16 15:44 [RFC] [PATCH net-next v5 0/3] r8169: Implement dynamic ASPM mechanism for recent 1.0/2.5Gbps Realtek NICs Kai-Heng Feng
2021-09-16 15:44 ` [RFC] [PATCH net-next v5 1/3] PCI/ASPM: Introduce a new helper to report ASPM capability Kai-Heng Feng
2021-09-16 15:44 ` [RFC] [PATCH net-next v5 2/3] r8169: Use PCIe ASPM status for NIC ASPM enablement Kai-Heng Feng
2021-09-16 17:07   ` Bjorn Helgaas
2021-09-17  4:09     ` Kai-Heng Feng
2021-09-17 15:26       ` Bjorn Helgaas
2021-10-01  4:32         ` Kai-Heng Feng [this message]
2021-09-16 15:44 ` [RFC] [PATCH net-next v5 3/3] r8169: Implement dynamic ASPM mechanism Kai-Heng Feng
2021-09-16 17:12   ` Bjorn Helgaas
2021-09-17  4:19     ` Kai-Heng Feng
2021-09-17 22:09 ` [RFC] [PATCH net-next v5 0/3] r8169: Implement dynamic ASPM mechanism for recent 1.0/2.5Gbps Realtek NICs Bjorn Helgaas
2021-10-01  4:17   ` Kai-Heng Feng
2021-10-07 19:10     ` Bjorn Helgaas
2021-10-08 13:56     ` Bjorn Helgaas

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