Re: [PATCH] cfg80211: Add cumulative channel survey dump support.

From: Ben Greear <greearb@candelatech.com>
To: Sven Eckelmann <sven@narfation.org>,
	ath10k@lists.infradead.org, sw@simonwunderlich.de
Cc: vnaralas@codeaurora.org, linux-wireless@vger.kernel.org,
	Johannes Berg <johannes@sipsolutions.net>,
	slakkavalli@datto.com
Subject: Re: [PATCH] cfg80211: Add cumulative channel survey dump support.
Date: Wed, 18 Sep 2019 05:58:46 -0700	[thread overview]
Message-ID: <b24ec622-8510-d8e4-bbc4-86a34c1dd32b@candelatech.com> (raw)
In-Reply-To: <18458963.ukFM9YuvQx@bentobox>

On 09/18/2019 01:46 AM, Sven Eckelmann wrote:
> On Tuesday, 17 September 2019 19:27:50 CEST Sven Eckelmann wrote:
> [...]
>> So whatever the firmware does when it gets a
>> WMI_BSS_SURVEY_REQ_TYPE_READ_CLEAR -  it is not a CLEAR after read. And they
>> also don't simply wrap around but there all values have to get some kind of
>> "fix" like the active time one shown in ath10k_hw_fill_survey_time.
>> Just that the actual "fixes" for them are unknown. To me it looks like
>> firmware ATH10K_HW_CC_WRAP_SHIFTED_ALL have busy and rx interlinked with
>> the overflow of total. But the tx and rx_bss are actually cleared.
>>
>> Other than that, the counters are wrapping every ~14-30 seconds. So we
>> also need also some worker for ath10k which every couple of seconds
>> requests new values for all the channel from the firmware. Which already
>> sounds problematic because I get
>> "ath10k_pci 0000:00:00.0: bss channelsurvey timed out" all the time
>> when requesting surveys manually.
>
> I've just tested it on 10.4 (wave-2) cards and it seems like it is cleared as
> expected on them. So the change I posted earlier (with a minor fix for
> ath10k_hw_fill_survey_time) returns now useful (accumulated) values. This can
> be seen in
> https://stats.freifunk-vogtland.net/d/ffv_node/nodeinfo?orgId=1&var-node=ac86749f4d60&fullscreen&panelId=5&from=1568782046974&to=1568807068706
> (after the reboot at 10:15 UTC+2)
>
> So as Ben Greear said, the 10.4 firmware version is fixed and 10.2.* (for
> the wave-1 cards) is still broken and we need a QCA firmware engineer to
> fix it. Or to work around it by polling every couple of seconds and
> manually do the cleanup of the values from the firmware.

Have you tried probing very fast, like every 100ms, to see if returned values
look sane?  I seem to recall that there was some firmware issue with this, like
it only updates internal counters every second or so.

Polling slow would have the same off-by-a-second's-worth-of-data, but you would not
easily notice it at slower polling intervals.

Thanks,
Ben

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

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