[Intel-wired-lan] [PATCH next-queue v1 2/2] igc: Reject schedules with a base_time in the future

[Brown, Aaron F]

> From: Intel-wired-lan <intel-wired-lan-bounces at osuosl.org> On Behalf Of
> Vinicius Costa Gomes
> Sent: Wednesday, September 2, 2020 4:37 PM
> To: intel-wired-lan at lists.osuosl.org
> Cc: Guedes, Andre <andre.guedes at intel.com>
> Subject: [Intel-wired-lan] [PATCH next-queue v1 2/2] igc: Reject schedules
> with a base_time in the future
> 
> When we set the BASET registers of i225 with a base_time in the
> future, i225 will "hold" all packets until that base_time is reached,
> causing a lot of TX Hangs.
> 
> As this behaviour seems contrary to the expectations of the IEEE
> 802.1Q standard (section 8.6.9, specially 8.6.9.4.5), let's start by
> rejecting these types of schedules. If this is too limiting, we can
> for example, setup a timer to configure the BASET registers closer to
> the start time, only blocking the packets for a "short" while.
> 
> Signed-off-by: Vinicius Costa Gomes <vinicius.gomes at intel.com>
> ---
>  drivers/net/ethernet/intel/igc/igc_main.c | 25 +++++++++++++++++++++--
>  1 file changed, 23 insertions(+), 2 deletions(-)
> 
Tested-by: Aaron Brown <aaron.f.brown at intel.com>