Re: i40e_aq_get_phy_capabilities() fails when using SFP+ with no link

[Olivier MATZ <olivier.matz@6wind.com>]

Hi Christos,

+CC i40e maintainers

On Tue, 10 Jan 2017 20:32:26 +0800, Christos Ricudis
<ricudis.christos@gmail.com> wrote:
> Hello, 
> 
> Using a X710 based 4-port 4x10Gbit NIC, I have came across the
> following issue on the i40e PMD: 
> 
> When an optical SFP+ (Finisar FTLX8571D3BCL) is used with no active
> link partner on the other end of the link (or fiber completely
> disconnected from the SFP+), i40e_aq_get_phy_capabilities() (called
> by i40e_dev_sync_phy_type() on port initialization), fails with a
> 0x05 return value (EIO) on the AQ response structure. The struct
> i40e_aq_get_phy_abilities_resp buffer passed to the Get Phy Abilities
> command is unmodified upon return. 
> 
> This prevents DPDK 16.11 from initializing the port, and ultimately
> fails with the following error: 
> 
> PMD: eth_i40e_dev_init(): Failed to sync phy type: -95
> 
> The change introducing this issue was
> http://dpdk.org/ml/archives/dev/2016-September/047663.html
> 
> Reading the X710 datasheet, I notice that no specific mention is
> given on the meaning of EIO as a response to Get PHY Abilities
> command (opcode 0x0600), whereas in most other commands, an explicit
> mention of the meaning of the possible error status responses is
> given. 
> 
> This behaviour is the same across the following NVM releases: 
> 
> FW 4.33 API 1.2 NVM 04.04.02 eetrack 800018a6
> FW 4.40 API 1.4 NVM 04.05.03 eetrack 80001cd8
> FW 5.0 API 1.5 NVM 05.00.04 eetrack 800024da
> 
> I will try to get around the issue by falling back to PHY
> capabilities detection using the device ID in the case
> i40e_aq_get_phy_capabilities() fails, but conceptually the
> capabilities of the PHY should not be dependent on whether PHY
> detects an active link or not. 
> 
> I’d be happy to do more testing on this issue per your
> recommendations. 
> 
> Moreover, while trying to debug this issue, I managed to get both 3
> NIC adapters on my test system on a state where the PHY has
> apparently died - no link indication at all on any ports. A reboot
> solved this, and I am now trying to replicate this behaviour under
> more controlled conditions. 
> 

I'm currently running into a similar issue (I think). I can reproduce
it with testpmd with the following case:

  set link_check off
  port stop 0
  # don't wait between these 2 commands
  port start 0

I added some logs that are displayed after the port start:

  PMD: i40e_set_tx_function(): Vector tx finally be used.
  PMD: i40e_set_rx_function(): Vector rx enabled, please make sure RX
    burst size no less than 4 (port=0).
  PMD: i40e_dev_rx_queue_start():  >>
  PMD: i40e_dev_tx_queue_start():  >>
  PMD: i40e_dev_start(): applying link settings...
  PMD: i40e_apply_link_speed(): abilities = 38, speed = 0
  PMD: i40e_phy_conf_link(): i40e_aq_get_phy_capabilities failed -7
  PMD: i40e_dev_start(): Fail to apply link setting
  PMD: i40e_dev_clear_queues():  >>

The -7 corresponds to I40E_ERR_UNKNOWN_PHY. This happens in
i40e_aq_get_phy_capabilities() in the following code, which makes me
think it's the same problem than yours:

	if (hw->aq.asq_last_status == I40E_AQ_RC_EIO)
		status = I40E_ERR_UNKNOWN_PHY;

A workaround in my usecase is to wait a bit between the stop and the
start.

Any help is welcome.

Regards,
Olivier