Re: [PATCH iwl-net v2 2/3] igc: Fix reset adapter logics when tx mode change

[Abdul Rahim, Faizal]

Hi Vinicius,

On 11/7/2024 6:44 am, Vinicius Costa Gomes wrote:
> Faizal Rahim <faizal.abdul.rahim@xxxxxxxxxxxxxxx> writes:
>
> > Following the "igc: Fix TX Hang issue when QBV Gate is close" changes,
> > remaining issues with the reset adapter logic in igc_tsn_offload_apply()
> > have been observed:
> >
> > 1. The reset adapter logics for i225 and i226 differ, although they should
> >     be the same according to the guidelines in I225/6 HW Design Section
> >     7.5.2.1 on software initialization during tx mode changes.
> > 2. The i225 resets adapter every time, even though tx mode doesn't change.
> >     This occurs solely based on the condition  igc_is_device_id_i225() when
> >     calling schedule_work().
> > 3. i226 doesn't reset adapter for tsn->legacy tx mode changes. It only
> >     resets adapter for legacy->tsn tx mode transitions.
> > 4. qbv_count introduced in the patch is actually not needed; in this
> >     context, a non-zero value of qbv_count is used to indicate if tx mode
> >     was unconditionally set to tsn in igc_tsn_enable_offload(). This could
> >     be replaced by checking the existing register
> >     IGC_TQAVCTRL_TRANSMIT_MODE_TSN bit.
> >
> > This patch resolves all issues and enters schedule_work() to reset the
> > adapter only when changing tx mode. It also removes reliance on qbv_count.
> >
> > qbv_count field will be removed in a future patch.
> >
> > Test ran:
> >
> > 1. Verify reset adapter behaviour in i225/6:
> >     a) Enrol a new GCL
> >        Reset adapter observed (tx mode change legacy->tsn)
> >     b) Enrol a new GCL without deleting qdisc
> >        No reset adapter observed (tx mode remain tsn->tsn)
> >     c) Delete qdisc
> >        Reset adapter observed (tx mode change tsn->legacy)
> >
> > 2. Tested scenario from "igc: Fix TX Hang issue when QBV Gate is closed"
> >     to confirm it remains resolved.
> >
> > Fixes: 175c241288c0 ("igc: Fix TX Hang issue when QBV Gate is closed")
> > Signed-off-by: Faizal Rahim <faizal.abdul.rahim@xxxxxxxxxxxxxxx>
> > Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
> > ---
>
> There were a quite a few bugs, some of them my fault, on this part of
> the code, changing between the modes in the hardware.
>
> So I would like some confirmation that ETF offloading/LaunchTime was
> also tested with this change. Just to be sure.
>
> But code-wise, looks good:
>
> Acked-by: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx>
>
>
> Cheers,


Tested etf with offload, looks like working correctly.

1. mqprio
tc qdisc add dev enp1s0 handle 100: parent root mqprio num_tc 3 \
map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 \
queues 1@0 1@1 2@2 \
hw 0

No reset adapter observed.

2. etf with offload
tc qdisc replace dev enp1s0 parent 100:1 etf \
clockid CLOCK_TAI delta 300000 offload

Reset adapter observed (tx mode legacy -> tsn).

3. delete qdisc
tc qdisc delete dev enp1s0 parent root handle 100

Reset adapter observed (tx mode tsn -> legacy).