On 2/24/23 7:46 PM, Kai-Heng Feng wrote:
> To really enable ASPM on r8169 NICs, both standard PCIe ASPM and
> chip-specific ASPM have to be enabled at the same time.
>
> Before enabling ASPM at chip side, make sure the following conditions
> are met:
> 1) Use pcie_aspm_support_enabled() to check if ASPM is disabled by
> kernel parameter.
> 2) Use pcie_aspm_capable() to see if the device is capable to perform
> PCIe ASPM.
Why not club the support check within pcie_aspm_capable()?
> 3) Check the return value of pci_disable_link_state(). If it's -EPERM,
> it means BIOS doesn't grant ASPM control to OS, and device should use
> the ASPM setting as is.
>
> Consider ASPM is manageable when those conditions are met.
>
> While at it, disable ASPM at chip-side for TX timeout reset, since
> pci_disable_link_state() doesn't have any effect when OS isn't granted
> with ASPM control.
>
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
> ---
> v9:
> - No change.
>
> v8:
> - Enable chip-side ASPM only when PCIe ASPM is already available.
> - Wording.
>
> v7:
> - No change.
>
> v6:
> - Unconditionally enable chip-specific ASPM.
>
> v5:
> - New patch.
>
> drivers/net/ethernet/realtek/r8169_main.c | 22 ++++++++++++++++++----
> 1 file changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
> index 45147a1016bec..a857650c2e82b 100644
> --- a/drivers/net/ethernet/realtek/r8169_main.c
> +++ b/drivers/net/ethernet/realtek/r8169_main.c
> @@ -2675,8 +2675,11 @@ static void rtl_disable_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) {
> + /* Skip if PCIe ASPM isn't possible */
> + if (!tp->aspm_manageable)
> + return;
> +
> + if (enable) {
> RTL_W8(tp, Config5, RTL_R8(tp, Config5) | ASPM_en);
> RTL_W8(tp, Config2, RTL_R8(tp, Config2) | ClkReqEn);
>
> @@ -4545,8 +4548,13 @@ static void rtl_task(struct work_struct *work)
> /* ASPM compatibility issues are a typical reason for tx timeouts */
> ret = pci_disable_link_state(tp->pci_dev, PCIE_LINK_STATE_L1 |
> PCIE_LINK_STATE_L0S);
> +
> + /* OS may not be granted to control PCIe ASPM, prevent the driver from using it */
> + tp->aspm_manageable = 0;
> +
> if (!ret)
> netdev_warn_once(tp->dev, "ASPM disabled on Tx timeout\n");
> +
> goto reset;
> }
>
> @@ -5227,13 +5235,19 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
> * Chips from RTL8168h partially have issues with L1.2, but seem
> * to work fine with L1 and L1.1.
> */
> - if (rtl_aspm_is_safe(tp))
> + if (!pcie_aspm_support_enabled() || !pcie_aspm_capable(pdev))
> + rc = -EINVAL;
> + else if (rtl_aspm_is_safe(tp))
> rc = 0;
> else if (tp->mac_version >= RTL_GIGA_MAC_VER_46)
> rc = pci_disable_link_state(pdev, PCIE_LINK_STATE_L1_2);
> else
> rc = pci_disable_link_state(pdev, PCIE_LINK_STATE_L1);
> - tp->aspm_manageable = !rc;
> +
> + /* -EPERM means BIOS doesn't grant OS ASPM control, ASPM should be use
> + * as is. Honor it.
> + */
> + tp->aspm_manageable = (rc == -EPERM) ? 1 : !rc;
>
> tp->dash_type = rtl_check_dash(tp);
>
--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer
