Re: [Intel-wired-lan] [iwl-net v2 1/2] igc: Fix missing time sync events

[naamax.meir]

On 2/21/2024 01:57, Vinicius Costa Gomes wrote:
> Fix "double" clearing of interrupts, which can cause external events
> or timestamps to be missed.
>
> The IGC_TSIRC Time Sync Interrupt Cause register can be cleared in two
> ways, by either reading it or by writing '1' into the specific cause
> bit. This is documented in section 8.16.1.
>
> The following flow was used:
>   1. read IGC_TSIRC into 'tsicr';
>   2. handle the interrupts present in 'tsirc' and mark them in 'ack';
>   3. write 'ack' into IGC_TSICR;
>
> As both (1) and (3) will clear the interrupt cause, if the same
> interrupt happens again between (1) and (3) it will be ignored,
> causing events to be missed.
>
> Remove the extra clear in (3).
>
> Fixes: 2c344ae24501 ("igc: Add support for TX timestamping")
> Reviewed-by: Kurt Kanzenbach <kurt@xxxxxxxxxxxxx>
> Tested-by: Kurt Kanzenbach <kurt@xxxxxxxxxxxxx> # Intel i225
> Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx>
> ---
>   drivers/net/ethernet/intel/igc/igc_main.c | 12 +-----------
>   1 file changed, 1 insertion(+), 11 deletions(-)

Tested-by: Naama Meir <naamax.meir@xxxxxxxxxxxxxxx>