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SubjectRE: [Intel-wired-lan] [iwl-net v2 2/2] igb: Fix missing time sync events
Date
> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of Vinicius Costa Gomes
> Sent: Wednesday, February 21, 2024 5:27 AM
> To: intel-wired-lan@lists.osuosl.org
> Cc: Neftin, Sasha <sasha.neftin@intel.com>; Gomes, Vinicius <vinicius.gomes@intel.com>; netdev@vger.kernel.org; richardcochran@gmail.com; kurt@linutronix.de; Brandeburg, Jesse <jesse.brandeburg@intel.com>; linux-kernel@vgerkernel.org; Eric Dumazet <edumazet@google.com>; Nguyen, Anthony L <anthonyl.nguyen@intel.com>; Jeff Kirsher <jeffrey.t.kirsher@intel.com>; Jakub Kicinski <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; David S. Miller <davem@davemloft.net>
> Subject: [Intel-wired-lan] [iwl-net v2 2/2] igb: Fix missing time sync events
>
> Fix "double" clearing of interrupts, which can cause external events
> or timestamps to be missed.
>
> The E1000_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 E1000_TSIRC into 'tsicr';
> 2. handle the interrupts present into 'tsirc' and mark them in 'ack';
> 3. write 'ack' into E1000_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: 00c65578b47b ("igb: enable internal PPS for the i210")
> Acked-by: Richard Cochran <richardcochran@gmail.com>
> Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
> ---
> drivers/net/ethernet/intel/igb/igb_main.c | 23 +++++------------------
> 1 file changed, 5 insertions(+), 18 deletions(-)
>

Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)


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