Re: [RFC PATCH v2] netpoll: Remove 4s sleep during carrier detection

From: Jakub Kicinski
Date: Fri Jan 20 2023 - 00:07:12 EST


On Thu, 19 Jan 2023 10:00:08 -0800 Breno Leitao wrote:
> This patch proposes to remove the msleep(4s) during netpoll_setup() if
> the carrier appears instantly.
>
> Modern NICs do not seem to have this bouncing problem anymore, and this
> sleep slows down the machine boot unnecessarily

We should mention in the message that the wait is counter-productive on
servers which have BMC communicating over NC-SI via the same NIC as gets
used for netconsole. BMC will keep the PHY up, hence the carrier
appearing instantly.

We could add a smaller delay, but really having instant carrier and
then loosing it seems like a driver bug, so let's try to rip the band
aid off and ask for forgiveness instead.


Few extra process rules:
- don't repost another version within 24h,
- keep a changelog under ---
- add tree name to the tag - [PATCH net-next]

Also, I'd just go for PATCH, no need to RFC this.
If someone wants to object they can object to a PATCH.