ACK/Cmnt: NAK: [SRU][F:linux-bluefield][PATCH v1 0/1] mlxbf_gige: increase MDIO polling rate to 5us

[Tim Gardner]

Acked-by: Tim Gardner <tim.gardner at canonical.com>

The review should still have complained about the proliferation of magic 
numbers. Its one of my pet peeves.

rtg

On 5/20/22 08:46, David Thompson wrote:
> Hello Tim,
> 
> This patch was already applied to net-next (see attached email)
> 
> - Dave
> 
>> -----Original Message-----
>> From: Tim Gardner <tim.gardner at canonical.com>
>> Sent: Friday, May 20, 2022 8:35 AM
>> To: David Thompson <davthompson at nvidia.com>; kernel-
>> team at lists.ubuntu.com
>> Cc: Meriton Tuli <meriton at nvidia.com>; Khoa Vo <khoav at nvidia.com>
>> Subject: NAK: [SRU][F:linux-bluefield][PATCH v1 0/1] mlxbf_gige: increase MDIO
>> polling rate to 5us
>>
>> This patch, though simple enough, has had no upstream review and should
>> therefore be an 'UBUNTU: SAUCE:' patch until such time as it is included in net-
>> next or linux-next. Furthermore, define a macro for the POLL time instead of
>> duplicating magic numbers in the code.
>>
>> rtg
>>
>> On 5/19/22 16:49, David Thompson wrote:
>>> BugLink: https://bugs.launchpad.net/bugs/1974246
>>>
>>> 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.
>>>
>>> David Thompson (1):
>>>     mlxbf_gige: increase MDIO polling rate to 5us
>>>
>>>    drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_mdio.c | 6 ++++--
>>>    1 file changed, 4 insertions(+), 2 deletions(-)
>>>
>>
>> --
>> -----------
>> Tim Gardner
>> Canonical, Inc

-- 
-----------
Tim Gardner
Canonical, Inc