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From: Timur Tabi <timur@codeaurora.org>
To: Florian Fainelli <f.fainelli@gmail.com>, netdev@vger.kernel.org
Subject: Re: Requirements for a shutdown function?
Date: Tue, 9 May 2017 13:51:28 -0500	[thread overview]
Message-ID: <f995d5b3-2a5c-df08-3915-f77ab9203844@codeaurora.org> (raw)
In-Reply-To: <1721db9b-ed60-4556-9aac-81f17e2c1849@gmail.com>

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.

-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc.  Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

  reply	other threads:[~2017-05-09 18:51 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-09 16:58 Requirements for a shutdown function? Timur Tabi
2017-05-09 18:46 ` Florian Fainelli
2017-05-09 18:51   ` Timur Tabi [this message]
2017-05-09 19:06     ` Florian Fainelli
2017-05-10 20:17       ` Timur Tabi
2017-05-10 21:47         ` Florian Fainelli
2017-05-10 22:11           ` Timur Tabi
2017-05-10 22:17             ` Florian Fainelli

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