Public bug reported:

SRU Justification:

[Impact]

There is MDIO logic within the mlxbf_gige driver that currently
polls for completed transactions every 100us.  This has been
reviewed and tested in the lab and found to be inefficient.

[Fix]

The fix is to modify the driver logic to increase the MDIO
polling rate to 5us.  With this change the amount of
time spent waiting for the MDIO BUSY signal to de-assert
drops from ~100us to ~27us for each operation.

[Test Case]

The driver should function as before, specifically:
* driver probes successfully
* oob_net0 link comes up, as seen with "ifconfig -a"
* reset and power cycle testing toggle PHY hardware,
  and oob_net0 link still comes up

[Regression Potential]

This change affects all MDIO transactions to the board-level
PHY device, and as such, could cause a regression with PHY
communications.  However, this change has been heavily tested.

** Affects: linux-bluefield (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1974246

Title:
  mlxbf_gige: increase MDIO polling rate

Status in linux-bluefield package in Ubuntu:
  New

Bug description:
  SRU Justification:

  [Impact]

  There is MDIO logic within the mlxbf_gige driver that currently
  polls for completed transactions every 100us.  This has been
  reviewed and tested in the lab and found to be inefficient.

  [Fix]

  The fix is to modify the driver logic to increase the MDIO
  polling rate to 5us.  With this change the amount of
  time spent waiting for the MDIO BUSY signal to de-assert
  drops from ~100us to ~27us for each operation.

  [Test Case]

  The driver should function as before, specifically:
  * driver probes successfully
  * oob_net0 link comes up, as seen with "ifconfig -a"
  * reset and power cycle testing toggle PHY hardware,
    and oob_net0 link still comes up

  [Regression Potential]

  This change affects all MDIO transactions to the board-level
  PHY device, and as such, could cause a regression with PHY
  communications.  However, this change has been heavily tested.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux-bluefield/+bug/1974246/+subscriptions


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