RE: [PATCH net-next 2/2] r8169: disable RTL8126 ZRX-DC timeout

[Hau <hau@realtek.com>]

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> 
> On 14.03.2025 08:50, ChunHao Lin wrote:
> > Disable it due to it dose not meet ZRX-DC specification. If it is
> > enabled,
> 
> dose -> does
> 
> > device will exit L1 substate every 100ms. Disable it for saving more
> > power in L1 substate.
> >
> > Signed-off-by: ChunHao Lin <hau@realtek.com>
> > ---
> >  drivers/net/ethernet/realtek/r8169_main.c | 16 ++++++++++++++++
> >  1 file changed, 16 insertions(+)
> >
> > diff --git a/drivers/net/ethernet/realtek/r8169_main.c
> > b/drivers/net/ethernet/realtek/r8169_main.c
> > index 3c663fca07d3..dfc96b09b85e 100644
> > --- a/drivers/net/ethernet/realtek/r8169_main.c
> > +++ b/drivers/net/ethernet/realtek/r8169_main.c
> > @@ -2852,6 +2852,21 @@ static u32 rtl_csi_read(struct rtl8169_private *tp,
> int addr)
> >               RTL_R32(tp, CSIDR) : ~0;  }
> >
> > +static void rtl_disable_zrxdc_timeout(struct rtl8169_private *tp) {
> > +     struct pci_dev *pdev = tp->pci_dev;
> > +     u8 val;
> > +
> > +     if (pdev->cfg_size > 0x0890 &&
> > +         pci_read_config_byte(pdev, 0x0890, &val) == PCIBIOS_SUCCESSFUL
> &&
> > +         pci_write_config_byte(pdev, 0x0890, val & ~BIT(0)) ==
> PCIBIOS_SUCCESSFUL)
> > +             return;
> > +
> > +     netdev_notice_once(tp->dev,
> > +             "No native access to PCI extended config space, falling back to
> CSI\n");
> > +     rtl_csi_write(tp, 0x0890, rtl_csi_read(tp, 0x0890) & ~BIT(0)); }
> > +
> 
> Does the datasheet have a name for this extended config space register and
> bit 0?
> This would be better than using magic numbers.

I will try to get the name of this bit.

> I think we can factor out the extended config space access to a helper. The
> same code we have in another place already. But this can be done as a
> follow-up.
> 
> >  static void rtl_set_aspm_entry_latency(struct rtl8169_private *tp, u8
> > val)  {
> >       struct pci_dev *pdev = tp->pci_dev; @@ -3824,6 +3839,7 @@ static
> > void rtl_hw_start_8125d(struct rtl8169_private *tp)
> >
> >  static void rtl_hw_start_8126a(struct rtl8169_private *tp)  {
> > +     rtl_disable_zrxdc_timeout(tp);
> >       rtl_set_def_aspm_entry_latency(tp);
> >       rtl_hw_start_8125_common(tp);
> >  }