Re: Requirements for a shutdown function?

On 05/09/2017 01:46 PM, Florian Fainelli wrote:

A good test case for exercising a .shutdown() function is kexec'ing a
new kernel for instance.

I tried that.  I run iperf in one window while launching kexec in another.
Even without a shutdown function, network traffic appear to halt on its own
and the kexec succeeds.

Is it possible that the network stack detects a kexec and automatically
stops all network devices?

You should put your HW in a state where it won't be doing DMA, or have
any adverse side effects to the system, putting it in a low power state
is also a good approach.

My in-house driver stops the RX and TX queues.  I'm guessing that's good
enough, but I don't have a failing test case to prove it.

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