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Subject: Re: [PATCH v3] wifi: ath11k: Optimize 6 GHz scan time
From:   Kalle Valo <kvalo@kernel.org>
In-Reply-To: <20230315112103.18426-1-quic_mpubbise@quicinc.com>
References: <20230315112103.18426-1-quic_mpubbise@quicinc.com>
To:     Manikanta Pubbisetty <quic_mpubbise@quicinc.com>
Cc:     <ath11k@lists.infradead.org>, <linux-wireless@vger.kernel.org>,
        Manikanta Pubbisetty <quic_mpubbise@quicinc.com>
User-Agent: pwcli/0.1.1-git (https://github.com/kvalo/pwcli/) Python/3.7.3
Message-ID: <167948612507.6445.2579526780286789940.kvalo@kernel.org>
Date:   Wed, 22 Mar 2023 11:55:29 +0000 (UTC)
Precedence: bulk

Manikanta Pubbisetty <quic_mpubbise@quicinc.com> wrote:

> Currently, time taken to scan all supported channels on WCN6750
> is ~8 seconds and connection time is almost 10 seconds. WCN6750
> supports three Wi-Fi bands (i.e., 2.4/5/6 GHz) and the numbers of
> channels for scan come around ~100 channels (default case).
> Since the chip doesn't have support for DBS (Dual Band Simultaneous),
> scans cannot be parallelized resulting in longer scan times.
> 
> Among the 100 odd channels, ~60 channels are in 6 GHz band. Therefore,
> optimizing the scan for 6 GHz channels will bring down the overall
> scan time.
> 
> WCN6750 firmware has support to scan a 6 GHz channel based on co-located
> AP information i.e., RNR IE which is found in the legacy 2.4/5 GHz scan
> results. When a scan request with all supported channel list is enqueued
> to the firmware, then based on WMI_SCAN_CHAN_FLAG_SCAN_ONLY_IF_RNR_FOUND
> scan channel flag, firmware will scan only those 6 GHz channels for which
> RNR IEs are found in the legacy scan results.
> 
> In the proposed design, based on NL80211_SCAN_FLAG_COLOCATED_6GHZ scan
> flag, driver will set the WMI_SCAN_CHAN_FLAG_SCAN_ONLY_IF_RNR_FOUND flag
> for non-PSC channels. Since there is high probability to find 6 GHz APs
> on PSC channels, these channels are always scanned. Only non-PSC channels
> are selectively scanned based on cached RNR information from the legacy
> scan results.
> 
> If NL80211_SCAN_FLAG_COLOCATED_6GHZ is not set in the scan flags,
> then scan will happen on all supported channels (default behavior).
> 
> With these optimizations, scan time is improved by 1.5-1.8 seconds on
> WCN6750. Similar savings have been observed on WCN6855.
> 
> Tested-on: WCN6750 hw1.0 AHB WLAN.MSL.1.0.1-00887-QCAMSLSWPLZ-1
> Tested-on: WCN6855 hw2.1 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.16
> 
> Signed-off-by: Manikanta Pubbisetty <quic_mpubbise@quicinc.com>
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>

New warning:

drivers/net/wireless/ath/ath11k/mac.c:3827: line length of 91 exceeds 90 columns

I couldn't quickly figure out how to fix that, any ideas?

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20230315112103.18426-1-quic_mpubbise@quicinc.com/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches