Re: [PATCH 0/3] mac80211: Trigger disconnect for STA during recovery

From: Ben Greear <greearb@candelatech.com>
To: Brian Norris <briannorris@chromium.org>
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
Date: Thu, 17 Dec 2020 14:57:24 -0800	[thread overview]
Message-ID: <6cec8a4c-620f-093d-2739-7eafe89cd79a@candelatech.com> (raw)
In-Reply-To: <X9vaqxub2F/8YPT8@google.com>

On 12/17/20 2:24 PM, Brian Norris wrote:
> 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.

I complain about all sorts of things, but I'm usually running
station mode :)

Do you actually see iwlwifi stations stay associated through
firmware crashes?

Anyway, happy to hear some have seamless recovery, and in that case,
I have no objections to the patch.

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com