Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Subject: Re: [PATCH] ath11k: reduce the wait time of 11d scan and hw scan
 while
 add interface
From:   Kalle Valo <kvalo@kernel.org>
In-Reply-To: <20220322124226.18347-1-quic_wgong@quicinc.com>
References: <20220322124226.18347-1-quic_wgong@quicinc.com>
To:     Wen Gong <quic_wgong@quicinc.com>
Cc:     <ath11k@lists.infradead.org>, <linux-wireless@vger.kernel.org>,
        <quic_wgong@quicinc.com>
User-Agent: pwcli/0.1.0-git (https://github.com/kvalo/pwcli/) Python/3.7.3
Message-ID: <164820512408.2234.13144214774407671269.kvalo@kernel.org>
Date:   Fri, 25 Mar 2022 10:45:26 +0000 (UTC)
Precedence: bulk

Wen Gong <quic_wgong@quicinc.com> wrote:

> Currently ath11k will wait 11d scan complete while add interface in
> ath11k_mac_op_add_interface(), when system resume without enable
> wowlan, ath11k_mac_op_add_interface() is called for each resume, thus
> it increase the resume time of system. And ath11k_mac_op_hw_scan()
> after ath11k_mac_op_add_interface() also needs some time cost because
> the previous 11d scan need more than 5 seconds when 6 GHz is enabled,
> then the scan started event will indicated to ath11k after the 11d
> scan completed.
> 
> While 11d scan/hw scan is running in firmware, if ath11k update channel
> list to firmware by WMI_SCAN_CHAN_LIST_CMDID, then firmware will cancel
> the current scan which is running, it lead the scan failed. The patch
> commit 9dcf6808b253 ("ath11k: add 11d scan offload support") used
> finish_11d_scan/finish_11d_ch_list/pending_11d to synchronize the 11d
> scan/hw scan/channel list between ath11k/firmware/mac80211 and to avoid
> the scan fail.
> 
> Add wait operation before ath11k update channel list, function
> ath11k_reg_update_chan_list() will wait until the current 11d scan/hw
> scan completed. And remove the wait operation of start 11d scan and
> waiting channel list complete in hw scan. After these changes, resume
> time cost reduce about 5 seconds and also hw scan time cost reduced
> obviously, and scan failed not seen.
> 
> The 11d scan is sent to firmware only one time for each interface added
> in mac.c, and it is moved after the 1st hw scan because 11d scan will
> cost some time and thus leads the AP scan result update to UI delay.
> Currently priority of ath11k's hw scan is WMI_SCAN_PRIORITY_LOW, and
> priority of 11d scan in firmware is WMI_SCAN_PRIORITY_MEDIUM, then the
> 11d scan which sent after hw scan will cancel the hw scan in firmware,
> so change the priority to WMI_SCAN_PRIORITY_MEDIUM for the hw scan which
> is in front of the 11d scan, thus it will not happen scan cancel in
> firmware.
> 
> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3
> 
> Fixes: 9dcf6808b253 ("ath11k: add 11d scan offload support")
> Signed-off-by: Wen Gong <quic_wgong@quicinc.com>
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>

I see new warnings in my regression tests:

[  755.217708] ath11k_pci 0000:06:00.0: failed to receive 11d scan complete: timed out
[  794.641670] ath11k_pci 0000:06:00.0: failed to receive 11d scan complete: timed out

Didn't investigate the patch in detail, gave up after seeing these warnings.

Patch set to Changes Requested.

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20220322124226.18347-1-quic_wgong@quicinc.com/

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