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Date:   Thu, 17 Dec 2020 14:24:43 -0800
From:   Brian Norris <briannorris@chromium.org>
To:     Ben Greear <greearb@candelatech.com>
Cc:     Youghandhar Chintala <youghand@codeaurora.org>,
        johannes@sipsolutions.net, ath10k@lists.infradead.org,
        kvalo@codeaurora.org, davem@davemloft.net, kuba@kernel.org,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, kuabhs@chromium.org,
        dianders@chromium.org, pillair@codeaurora.org
Subject: Re: [PATCH 0/3] mac80211: Trigger disconnect for STA during recovery
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References: <20201215172113.5038-1-youghand@codeaurora.org>
 <18dfa52b-5edd-f737-49c9-f532c1c10ba2@candelatech.com>
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On Tue, Dec 15, 2020 at 10:23:33AM -0800, Ben Greear wrote:
> On 12/15/20 9:21 AM, Youghandhar Chintala wrote:
> > From: Rakesh Pillai <pillair@codeaurora.org>
> > 
> > Currently in case of target hardware restart ,we just reconfig and
> > re-enable the security keys and enable the network queues to start
> > data traffic back from where it was interrupted.
> 
> Are there any known mac80211 radios/drivers that *can* support seamless restarts?
> 
> If not, then just could always enable this feature in mac80211?

I'm quite sure that iwlwifi intentionally supports a seamless restart.
From my experience with dealing with user reports, I don't recall any
issues where restart didn't function as expected, unless there was some
deeper underlying failure (e.g., hardware/power failure; driver bugs /
lockups).

I don't have very good stats for ath10k/QCA6174, but it survives
our testing OK and I again don't recall any user-reported complaints in
this area. I'd say this is a weaker example though, as I don't have as
clear of data. (By contrast, ath10k/WCN399x, which Rakesh, et al, are
patching here, does not pass our tests at all, and clearly fails to
recover from "seamless" restarts, as noted in patch 3.)

I'd also note that we don't operate in AP mode -- only STA -- and IIRC
Ben, you've complained about AP mode in the past.

Brian