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

[Mor Bar-Gabay]

On 07/07/2024 15:53, Faizal Rahim wrote:
> 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>
> Acked-by: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx>
> Acked-by: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx>
> ---
>   drivers/net/ethernet/intel/igc/igc_tsn.c | 23 ++++++++++++++++++++---
>   1 file changed, 20 insertions(+), 3 deletions(-)
Tested-by: Mor Bar-Gabay <morx.bar.gabay@xxxxxxxxx>