[PATCH 0/1][SRU][H/OEM-5.13/OEM-5.14/U] UBUNTU: SAUCE: Fix invalid MAC address after hotplug tbt dock

[Kai-Heng Feng]

On Wed, Sep 8, 2021 at 8:40 PM Aaron Ma <aaron.ma at canonical.com> wrote:
>
>
> On 9/8/21 8:06 PM, Tim Gardner wrote:
> >
> > Ick. It seems like there ought to be a more deterministic way to note when the MAC address has been copied. Why not a loop that does an msleep(1) until the MAC is address is updated or 600 msec elapses ?
>
> The MAC address of dock will read out at first, after 600 msec the MAC in BIOS will be updated.
> Driver doesn't know which one is the right MAC address. This allows enough time for hardware to update the

According to [1], there _can_ be IRQ raised when MAC update is
completed. So it's a good idea to check it.
If there's no IRQ from FW at current stage, then this is an unpleasant
but necessary workaround.

[1] https://lore.kernel.org/netdev/20daa122-aaec-0c6b-23f5-d2be2fcab1e9@intel.com/

Kai-Heng

>
> MAC address.
>
> Aaron
>
> >
> > On 9/8/21 2:49 AM, Aaron Ma wrote:
> >> BugLink: https://bugs.launchpad.net/bugs/1942999
> >>
> >> SRU justification:
> >>
> >> [Impact]
> >> igc driver can not connect to network after re-plugin thunderbolt dock
> >> when
> >> MAC passthrough enabled in BIOS.
> >>
> >> [Fix]
> >> Wait for the MAC copy of BIOS when enabled MAC passthrough.
> >> Intel engineer wants a different solution and promise to discuss with
> >> firmware engineer.
> >> Due to the schedule, made this as a short term solution to fix the
> >> issue, and wait for the other
> >> fix from Intel.
> >>
> >> [Test]
> >> Verified on hardware, after hotplug the thunderbolt cable,
> >> Ethernet works fine.
> >>
> >> [Where problems could occur]
> >> It may break the igc driver.
> >>
> >> Aaron Ma (1):
> >>    UBUNTU: SAUCE: igc: wait for the MAC copy when enabled MAC passthrough
> >>
> >>   drivers/net/ethernet/intel/igc/igc_main.c | 3 +++
> >>   1 file changed, 3 insertions(+)
> >>
> >
>
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