Upcoming 19.07.7 release

[Jaap Buurman]

On Sun, Feb 7, 2021 at 11:23 AM Baptiste Jonglez
<baptiste at bitsofnetworks.org> wrote:
>
> On 05-02-21, Jaap Buurman wrote:
> > > Hi,
> > >
> > > We are planning a new 19.07 release in about a week (probably next week-end).
> > >
> > > If you are aware of changes that need to be integrated, now is the time to
> > > do it or mention it here!
> > >
> > > I plan to test & integrate a workaround for this ramips stability issue:
> > > https://bugs.openwrt.org/index.php?do=details&task_id=2628
> > >
> > > Baptiste
> > >
> > > PS: please don't ask about 21.XX
> >
> > Dear Baptiste,
> >
> > Out of interest, what workaround for the RAMIPS stability issue are
> > you planning on using? Is it the disabling of TSO as discussed in the
> > bug report you have linked to?
>
> Yes, that's the idea, if it turns out to be not too intrusive.
>
> It's clearly a workaround from some other issue: as stated in the bug
> report, we use another driver in 5.4 and this one has no issue with TSO.
>
> Baptiste

Are we sure disabling TSO is the actual fix though? There are a few
reasons I am doubting that assessment:

1. Here is a user that is reporting he has always been running with
TSO disabled, yet he does experience the bug:
https://forum.openwrt.org/t/mtk-soc-eth-watchdog-timeout-after-r11573/50000/389?u=mushoz
2. TSO seems fine with the master branch according to user reports.
3. The user "mrakotiq" suggested a patch to disable TSO in the bug
report you linked to, but this bug report also disables
NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX. The reason that was
given was that he was seeing packets getting tagged that shouldn't
have (at least that's what I am understanding from his post on the bug
report). So there's obviously also something wrong with this
functionality, and it might not surprise me if this change is the
thing that seems to fix this issue.

Having said that, this bug is age-old and is affecting a lot of users,
me included. So I'd really like to get fixed. If there are no
regression with this approach, the best way forward might be to simply
adapt the patch he suggested as a workaround until we're on 21.xx with
the DSA driver. Especially since this user is reporting no more issues
with 75 (!) mt7621 routers in his production network, which is a
rather large sample size. Thoughts?

Jaap