[PATCH] wifi: ath12k: indicate to mac80211 scan complete with aborted flag for ATH12K_SCAN_STARTING state

[Jeff Johnson]

On 9/5/2023 3:59 AM, Wen Gong wrote:
> Scan failure can not be recovered from when running a loop of the
> following steps:
> 1. run scan: "iw wlan scan".
> 2. run command: echo assert > /sys/kernel/debug/ath12k/wcn7850\ hw2.0/simulate_fw_crash
>     immediately after step 1.
> 
> result:
> scan failed and can not recover even when wlan recovery succeeds:
> command failed: Device or resource busy (-16)
> 
> reason:
> When scan arrives, WMI_START_SCAN_CMDID is sent to the firmware and
> function ath12k_mac_op_hw_scan() returns, then simulate_fw_crash arrives
> and the scan started event does not arrive, and then it starts to do
> recovery of wlan. __ath12k_mac_scan_finish() which is called from
> ath12k_core_halt() is one step of recovery, it will not call
> ieee80211_scan_completed() by logic currently because the scan state is
> ATH12K_SCAN_STARTING. Thus it leads the scan not being completed in
> mac80211, and leads all consecutive scans failing with -EBUSY in
> nl80211_trigger_scan even after wlan recovery success.
> 
> Indicate scan complete with aborted flag to mac80211 for
> ATH12K_SCAN_STARTING to allow recovery from scan failed with "Device or
> resource busy (-16)" after wlan recovery.
> 
> Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0-03427-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.15378.4
> 
> Signed-off-by: Wen Gong <quic_wgong at quicinc.com>

Acked-by: Jeff Johnson <quic_jjohnson at quicinc.com>

> ---
>   drivers/net/wireless/ath/ath12k/mac.c | 15 +++++++++------
>   1 file changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
> index 0f2af2f14ef7..a99324dbe7ad 100644
> --- a/drivers/net/wireless/ath/ath12k/mac.c
> +++ b/drivers/net/wireless/ath/ath12k/mac.c
> @@ -2780,18 +2780,21 @@ void __ath12k_mac_scan_finish(struct ath12k *ar)
>   		break;
>   	case ATH12K_SCAN_RUNNING:
>   	case ATH12K_SCAN_ABORTING:
> +		if (ar->scan.is_roc && ar->scan.roc_notify)
> +			ieee80211_remain_on_channel_expired(ar->hw);
> +		fallthrough;
> +	case ATH12K_SCAN_STARTING:
>   		if (!ar->scan.is_roc) {
>   			struct cfg80211_scan_info info = {
> -				.aborted = (ar->scan.state ==
> -					    ATH12K_SCAN_ABORTING),
> +				.aborted = ((ar->scan.state ==
> +					    ATH12K_SCAN_ABORTING) ||
> +					    (ar->scan.state ==
> +					    ATH12K_SCAN_STARTING)),
>   			};
>   
>   			ieee80211_scan_completed(ar->hw, &info);
> -		} else if (ar->scan.roc_notify) {
> -			ieee80211_remain_on_channel_expired(ar->hw);
>   		}
> -		fallthrough;
> -	case ATH12K_SCAN_STARTING:
> +
>   		ar->scan.state = ATH12K_SCAN_IDLE;
>   		ar->scan_channel = NULL;
>   		ar->scan.roc_freq = 0;
> 
> base-commit: 3f257461ab0ab19806bae2bfde4c3cd88dbf050e