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

From: Ben Greear
Date: Thu Dec 17 2020 - 17:58:08 EST


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@xxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com