Re: [PATCH net-next 3/4] igb: enable internal PPS for the i210.

[Richard Cochran <richardcochran@gmail.com>]

On Tue, Nov 18, 2014 at 12:06:24AM +0100, Richard Cochran wrote:
> --- a/drivers/net/ethernet/intel/igb/igb_main.c
> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> @@ -5386,8 +5386,14 @@ void igb_update_stats(struct igb_adapter *adapter,
>  static void igb_tsync_interrupt(struct igb_adapter *adapter)
>  {
>  	struct e1000_hw *hw = &adapter->hw;
> +	struct ptp_clock_event event;
>  	u32 tsicr = rd32(E1000_TSICR);
>  
> +	if (tsicr & TSINTR_SYS_WRAP) {
> +		event.type = PTP_CLOCK_PPS;
> +		ptp_clock_event(adapter->ptp_clock, &event);

This causes a BUG for the 82580. When you enable E1000_TSICR_TXTS, it
seems that TSINTR_SYS_WRAP is also automatically enabled. Because the
82580 variant has no pps device enabled, the driver then dereferences
a null pointer.

So we need to make the call to ptp_clock_event() conditional based on
whether pps is enabled. I'll fix this in V2.

> +	}
> +

Thanks,
Richard