Re: [PATCH net-next] net: fec: Always call fec_restart() in resume path

[John Ernberg]

On 2/14/24 15:52, Jakub Kicinski wrote:
> On Wed, 14 Feb 2024 08:27:02 +0000 John Ernberg wrote:
>> You are correct, we thought so too at [1], but bisection is really hard
>> because we need a whole bunch of patches on top to even boot the system
>> (imx8qxp specific stuff in the NXP vendor tree that's difficult to
>> rebase), we left it a bit open ended.
>>
>> Over the course of the weekend I lost all confidence in my bisection
>> after being confident for 4-5 days, because the more I thought about it
>> the less it made sense for that commit to be the culprit.
>>
>> I should probably have both followed up on that mail with that, and been
>> clearer here. I apologize for failing that.
> 
> Is it perhaps possible that upstream 5.10 also didn't work?
> I'm not saying the change itself is incorrect, indeed there
> is fec_restart() on probe and open paths, as you say.
> Did you try reverting as many of the changes that happened
> in the meantime as possible (instead of bisection)?
> 

That's a really good point. I'll make some time for this in the next weeks.
Please mark it with changes requested in the meantime, as I expect to 
make changes to the patch when I have a result.

> The other question is whether we need to enable any of the
> clocks or runtime resume before calling fec_restart()?

On our board it works fine without it, I don't know enough about this 
SoC or other NXP SoCs to know if it's necessary in other situations.

The clocks are re-enabled in the open call which appears to be enough to 
get traffic going again when the link is brought up.

Perhaps NXP can fill us in?

Thanks! // John Ernberg