[dpdk-dev] 2nd try: problem with ixgbe_dev_link_update() for multi-speed fiber [was] Re: [PATCH v4] net/ixgbe: ensure link status is updated

[Roger B. Melton]

Hi Laurent/Wei,

Any thoughts?

Regards,
Roger


On 5/17/17 9:31 AM, Roger B Melton wrote:
> Hi Laurent/Wei,
>
> As I continue to integrate DPDK 17.05 into my application, I have hit 
> another issue with this patch while testing in a VM with multispeed 
> fiber ixgbe PCI passthrough.  My application periodically invokes 
> rte_eth_link_get_nowait() to detect link state changes.  If the link 
> is down (no cable or far end disabled), ixgbe_setup_link() will not 
> return for ~1.3seconds due to the link setup algorithm in 
> ixgbe_common.c:ixgbe_multispeed_fiber():
>
> +    if ((intr->flags & IXGBE_FLAG_NEED_LINK_CONFIG) &&
> +        hw->mac.ops.get_media_type(hw) == ixgbe_media_type_fiber) {
> +        speed = hw->phy.autoneg_advertised;
> +        if (!speed)
> +            ixgbe_get_link_capabilities(hw, &speed, &autoneg);
> +        ixgbe_setup_link(hw, speed, true); +    }
> +
>
> I have two questions:
>
>  * Shouldn't we avoid the link setup cost if the caller has specified
>    not to wait_to_complete?
>  * If the concern is speed may not be properly configured, shouldn't
>    the link setup be deferred until state changes link up thus
>    minimizing the delays enforced in ixgbe_multispeed_fiber()?
>
>
> Regards,
> -Roger
>
>
>
>
> On 4/27/17 11:03 AM, Laurent Hardy wrote:
>> In case of fiber and link speed set to 1Gb at peer side (with autoneg
>> or with defined speed), link status could be not properly updated at
>> time cable is plugged-in.
>> Indeed if cable was not plugged when device has been configured and
>> started then link status will not be updated properly with new speed
>> as no link setup will be triggered.
>>
>> To avoid this issue, IXGBE_FLAG_NEED_LINK_CONFIG is set to try a link
>> setup each time link_update() is triggered and current link status is
>> down. When cable is plugged-in, link setup will be performed via
>> ixgbe_setup_link().
>>
>> Signed-off-by: Laurent Hardy <laurent.hardy at 6wind.com>
>> ---
>> Hi Wei, please find enclosed patch v4, tested using testpmd.
>>
>> v1 -> v2:
>> - rebase on top of head (change flag to 1<<4)
>> - fix regression with copper links: only update link for fiber links
>>
>> v2 -> v3:
>> - remove unnescessary check on speed mask if autoneg is false
>>
>> v3 -> v4:
>> - remove default speed set to 10Gb if autoneg is false, rely on
>> ixgbe_get_link_capabilities( ) instead.
>> ---
>>   drivers/net/ixgbe/ixgbe_ethdev.c | 14 ++++++++++++++
>>   drivers/net/ixgbe/ixgbe_ethdev.h |  1 +
>>   2 files changed, 15 insertions(+)
>>
>> diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c 
>> b/drivers/net/ixgbe/ixgbe_ethdev.c
>> index 7b856bb..8a0c0a7 100644
>> --- a/drivers/net/ixgbe/ixgbe_ethdev.c
>> +++ b/drivers/net/ixgbe/ixgbe_ethdev.c
>> @@ -3782,8 +3782,12 @@ ixgbe_dev_link_update(struct rte_eth_dev *dev, 
>> int wait_to_complete)
>>       struct ixgbe_hw *hw = 
>> IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
>>       struct rte_eth_link link, old;
>>       ixgbe_link_speed link_speed = IXGBE_LINK_SPEED_UNKNOWN;
>> +    struct ixgbe_interrupt *intr =
>> + IXGBE_DEV_PRIVATE_TO_INTR(dev->data->dev_private);
>>       int link_up;
>>       int diag;
>> +    u32 speed = 0;
>> +    bool autoneg = false;
>>         link.link_status = ETH_LINK_DOWN;
>>       link.link_speed = 0;
>> @@ -3793,6 +3797,14 @@ ixgbe_dev_link_update(struct rte_eth_dev *dev, 
>> int wait_to_complete)
>>         hw->mac.get_link_status = true;
>>   +    if ((intr->flags & IXGBE_FLAG_NEED_LINK_CONFIG) &&
>> +        hw->mac.ops.get_media_type(hw) == ixgbe_media_type_fiber) {
>> +        speed = hw->phy.autoneg_advertised;
>> +        if (!speed)
>> +            ixgbe_get_link_capabilities(hw, &speed, &autoneg);
>> +        ixgbe_setup_link(hw, speed, true);
>> +    }
>> +
>>       /* check if it needs to wait to complete, if lsc interrupt is 
>> enabled */
>>       if (wait_to_complete == 0 || dev->data->dev_conf.intr_conf.lsc 
>> != 0)
>>           diag = ixgbe_check_link(hw, &link_speed, &link_up, 0);
>> @@ -3810,10 +3822,12 @@ ixgbe_dev_link_update(struct rte_eth_dev 
>> *dev, int wait_to_complete)
>>         if (link_up == 0) {
>>           rte_ixgbe_dev_atomic_write_link_status(dev, &link);
>> +        intr->flags |= IXGBE_FLAG_NEED_LINK_CONFIG;
>>           if (link.link_status == old.link_status)
>>               return -1;
>>           return 0;
>>       }
>> +    intr->flags &= ~IXGBE_FLAG_NEED_LINK_CONFIG;
>>       link.link_status = ETH_LINK_UP;
>>       link.link_duplex = ETH_LINK_FULL_DUPLEX;
>>   diff --git a/drivers/net/ixgbe/ixgbe_ethdev.h 
>> b/drivers/net/ixgbe/ixgbe_ethdev.h
>> index 5176b02..b576a6f 100644
>> --- a/drivers/net/ixgbe/ixgbe_ethdev.h
>> +++ b/drivers/net/ixgbe/ixgbe_ethdev.h
>> @@ -45,6 +45,7 @@
>>   #define IXGBE_FLAG_MAILBOX          (uint32_t)(1 << 1)
>>   #define IXGBE_FLAG_PHY_INTERRUPT    (uint32_t)(1 << 2)
>>   #define IXGBE_FLAG_MACSEC           (uint32_t)(1 << 3)
>> +#define IXGBE_FLAG_NEED_LINK_CONFIG (uint32_t)(1 << 4)
>>     /*
>>    * Defines that were not part of ixgbe_type.h as they are not used 
>> by the
>
> .
>