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SubjectRe: Opportunistic S0ix blocked by e1000e when ethernet is in use
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Hi Jeffrey,

at 19:08, Kai-Heng Feng <kai.heng.feng@canonical.com> wrote:

> Hi Jeffrey,
>
> There are several platforms that uses e1000e can’t enter Opportunistic
> S0ix (PC10) when the ethernet has a link partner.
>
> This behavior also exits in out-of-tree e1000e driver 3.4.2.1, but seems
> like 3.4.2.3 fixes the issue.
>
> A quick diff between the two versions shows that this code section may be
> our solution:
>
> /* Read from EXTCNF_CTRL in e1000_acquire_swflag_ich8lan function
> * may occur during global reset and cause system hang.
> * Configuration space access creates the needed delay.
> * Write to E1000_STRAP RO register E1000_PCI_VENDOR_ID_REGISTER value
> * insures configuration space read is done before global reset.
> */
> pci_read_config_word(hw->adapter->pdev, E1000_PCI_VENDOR_ID_REGISTER,
> &pci_cfg);
> ew32(STRAP, pci_cfg);
> e_dbg("Issuing a global reset to ich8lan\n");
> ew32(CTRL, (ctrl | E1000_CTRL_RST));
> /* cannot issue a flush here because it hangs the hardware */
> msleep(20);
>
> /* Configuration space access improve HW level time sync mechanism.
> * Write to E1000_STRAP RO register E1000_PCI_VENDOR_ID_REGISTER
> * value to insure configuration space read is done
> * before any access to mac register.
> */
> pci_read_config_word(hw->adapter->pdev, E1000_PCI_VENDOR_ID_REGISTER,
> &pci_cfg);
> ew32(STRAP, pci_cfg);

Turns out the "extra sauce” is not this part, it’s called “Dynamic LTR
support”.

>
> Is there any plan to support this in the upstream kernel?

Is there any plan to support Dynamic LTR in upstream e1000e?

Kai-Heng

>
> Kai-Heng


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