On Thu, Nov 10, 2016 at 04:04:27AM -0800, Satha Rao wrote:
> i40e_asq_send_command: rd32 & wr32 under ThunderX gives unpredictable
> results. To solve this include rte memory barriers
>
> Signed-off-by: Satha Rao <skoteshwar at caviumnetworks.com>
> ---
> drivers/net/i40e/base/i40e_adminq.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/i40e/base/i40e_adminq.c
> b/drivers/net/i40e/base/i40e_adminq.c
> index 0d3a83f..1038a95 100644
> --- a/drivers/net/i40e/base/i40e_adminq.c
> +++ b/drivers/net/i40e/base/i40e_adminq.c
> @@ -832,6 +832,7 @@ enum i40e_status_code i40e_asq_send_command(struct
> i40e_hw *hw,
> }
>
> val = rd32(hw, hw->aq.asq.head);
> + rte_rmb();
use rte_smp_rmb() variant to avoid performance regression on x86
> if (val >= hw->aq.num_asq_entries) {
> i40e_debug(hw, I40E_DEBUG_AQ_MESSAGE,
> "AQTX: head overrun at %d\n", val);
> @@ -929,8 +930,10 @@ enum i40e_status_code i40e_asq_send_command(struct
> i40e_hw *hw,
> (hw->aq.asq.next_to_use)++;
> if (hw->aq.asq.next_to_use == hw->aq.asq.count)
> hw->aq.asq.next_to_use = 0;
> - if (!details->postpone)
> + if (!details->postpone) {
> wr32(hw, hw->aq.asq.tail, hw->aq.asq.next_to_use);
> + rte_wmb();
ditto
> + }
>
> /* if cmd_details are not defined or async flag is not set,
> * we need to wait for desc write back
> --
> 2.7.4
>
