Re: [PATCH] brcmfmac: include missing AP scan feature

["Alvin Šipraga" <ALSI@bang-olufsen.dk>]

Hi James,

James Prestwood <prestwoj@gmail.com> writes:

> This driver does not advertise this feature yet scanning with on an
> AP interface appears to work just fine.
> ---
>  drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> I've submitted this patch mainly to start a discussion about it. I
> find it hard to believe that ALL brcmfmac devices support AP scanning
> in which case this feature needs to be limited to those devices
> only. Trouble is there is no FW feature for AP scanning AFAIK.
>
> In any case I think this driver needs to sort out if it supports this
> feature or not, and advertise as such rather than leaving userspace
> in the dark.

By the way, what are the typical use-cases for AP scanning?

I know that hostapd does a passive scan on the AP interface on the
assumption that the driver/firmware will gather channel survey data, but
that's not a universally applicable assumption. Not all implementations
will do that.

Kind regards,
Alvin

>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> index fb727778312c..b6a50e65dbf6 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> @@ -7729,6 +7729,8 @@ struct brcmf_cfg80211_info *brcmf_cfg80211_attach(struct brcmf_pub *drvr,
>  #endif
>  	}
>  
> +	wiphy->features |= NL80211_FEATURE_AP_SCAN;
> +
>  	return cfg;
>  
>  detach: