Re: [PATCH 1/2] wifi: mt76: fix multi-radio on-channel scanning

[Ben Greear <greearb@candelatech.com>]

On 11/18/25 2:27 AM, Felix Fietkau wrote:
> From: Chad Monroe <chad@monroe.io>
> 
> avoid unnecessary channel switch when performing an on-channel scan
> using a multi-radio device.
> 
> Fixes: c56d6edebc1f ("wifi: mt76: mt7996: use emulated hardware scan support")
> Signed-off-by: Chad Monroe <chad@monroe.io>
> Signed-off-by: Felix Fietkau <nbd@nbd.name>
> ---
>   drivers/net/wireless/mediatek/mt76/scan.c | 12 +++++++-----
>   1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/wireless/mediatek/mt76/scan.c b/drivers/net/wireless/mediatek/mt76/scan.c
> index ff9176cdee3d..0b1922f7792e 100644
> --- a/drivers/net/wireless/mediatek/mt76/scan.c
> +++ b/drivers/net/wireless/mediatek/mt76/scan.c
> @@ -16,7 +16,7 @@ static void mt76_scan_complete(struct mt76_dev *dev, bool abort)
>   
>   	clear_bit(MT76_SCANNING, &phy->state);
>   
> -	if (dev->scan.chan && phy->main_chandef.chan &&
> +	if (dev->scan.chan && phy->main_chandef.chan && phy->offchannel &&
>   	    !test_bit(MT76_MCU_RESET, &dev->phy.state))
>   		mt76_set_channel(phy, &phy->main_chandef, false);
>   	mt76_put_vif_phy_link(phy, dev->scan.vif, dev->scan.mlink);
> @@ -94,7 +94,7 @@ void mt76_scan_work(struct work_struct *work)
>   		return;
>   	}
>   
> -	if (dev->scan.chan && phy->num_sta) {
> +	if (dev->scan.chan && phy->num_sta && phy->offchannel) {
>   		dev->scan.chan = NULL;
>   		mt76_set_channel(phy, &phy->main_chandef, false);
>   		goto out;
> @@ -102,20 +102,22 @@ void mt76_scan_work(struct work_struct *work)
>   
>   	dev->scan.chan = req->channels[dev->scan.chan_idx++];
>   	cfg80211_chandef_create(&chandef, dev->scan.chan, NL80211_CHAN_HT20);
> -	mt76_set_channel(phy, &chandef, true);
> +	if (dev->scan.chan != phy->main_chandef.chan)
> +		mt76_set_channel(phy, &chandef, true);

Do you still need to call the cfg80211_chandef_create(&chandef, dev->scan.chan, NL80211_CHAN_HT20);
method above if scan.chan == main_chandef.chan?

Thanks,
Ben

>   
>   	if (!req->n_ssids ||
>   	    chandef.chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
>   		goto out;
>   
> -	duration = HZ / 16; /* ~60 ms */
> +	if (phy->offchannel)
> +		duration = HZ / 16; /* ~60 ms */
>   	local_bh_disable();
>   	for (i = 0; i < req->n_ssids; i++)
>   		mt76_scan_send_probe(dev, &req->ssids[i]);
>   	local_bh_enable();
>   
>   out:
> -	if (dev->scan.chan)
> +	if (dev->scan.chan && phy->offchannel)
>   		duration = max_t(int, duration,
>   			         msecs_to_jiffies(req->duration +
>   						  (req->duration >> 5)));


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