On 2/9/24 23:11, Andrew Lunn wrote:
On Fri, Feb 09, 2024 at 01:59:44PM -0800, Jakub Kicinski wrote:
On Thu, 8 Feb 2024 10:52:29 +0100 David Ventura wrote:
During IP auto configuration, some drivers apparently need to wait a
certain length of time to settle; as this is not true for all drivers,
make this length of time configurable.
Please CC folks who gave you feedback, Andrew's is missing.
Thanks for the feedback, still learning this workflow
Andrew, what do you think about just removing the wait?
Or decreasing it to 1ms?
It feels a little wasteful to be adding uAPI for something
which as you said is likely papering over ancient bugs. We'll
fix the bugs which are still around and the uAPI will stay
forever :(
My guess is, the broken drivers are doing setup stuff after they call
netdev_register().
Reducing it to 1ms will probably continue to hide such bugs. So we
could just go with that, and probably not see any regressions. Or we
can decide we really do want to know about broken drivers, and just
remove the delay.
Either way, we don't need a new uAPI.
Would it make sense to move this to a build-time configuration flag?
I do not have a gut-feeling for which behaviors should be configurable
at build vs run time.
David, is 1ms too long for you? If we do take the delay out, you are
going to receive some of the flack from regression reports.
I've used this patch to experiment with different values, and the sleep time
behaves as described in Documentation/timers/timers-howto.rst, that is, a
call of `msleep(1)` usually delays boot time by 12~13 ms in my tests.
On top of this, I'm running this specific example on a no-smp systemm,
where I
do not believe the `msleep` achieves anything (but I'm a kernel newbie
so please
correct me if I'm wrong).
Andrew
