Re: Max clients on wifi access point with 7265

[Luca Coelho <luca@coelho.fi>]

On Mon, 2018-02-19 at 11:26 +0200, Luca Coelho wrote:
> On Mon, 2018-02-19 at 08:07 +0200, Kalle Valo wrote:
> > Steve deRosier <derosier@gmail.com> writes:
> > 
> > > On Wed, Feb 14, 2018 at 2:04 PM, Samuel Sieb <samuel@sieb.net>
> > > wrote:
> > > > On 02/14/2018 03:30 AM, Johannes Berg wrote:
> > > > > 
> > > > > On Wed, 2018-02-14 at 10:55 +0000, Mickaël PANNEQUIN wrote:
> > > > > 
> > > > > > 
> > > > > > Do you know the limit of the number of users connected at
> > > > > > the
> > > > > > same
> > > > > > time on the wifi? Works fine with 14 connected devices but
> > > > > > not more.
> > > > > > 
> > > > > > How to increase it?
> > > > > 
> > > > > 
> > > > > You can't.
> > > > > 
> > > > > > This limit is hardware?
> > > > > 
> > > > > 
> > > > > More or less, yes. The HW/FW can support 16 STAs, but needs
> > > > > two
> > > > > for
> > > > > other bookkeeping.
> > > > 
> > > > 
> > > > As a general question, is there a standard way to determine
> > > > this
> > > > limit for
> > > > any particular hardware?
> > > 
> > > 
> > > Yes, but there's no easy way. Put it in AP mode and connect
> > > clients
> > > to
> > > it until it starts rejecting new clients or dropping the old
> > > ones.
> > > Usually while watching it with a sniffer. That's how I've always
> > > had
> > > to do it.
> > > 
> > > Different chips will have different limits, and there's no
> > > reliable
> > > way to determine the limit across all chips other than trial and
> > > error. It seems a common desire of people to try to use client
> > > chips
> > > as poor-man APs. While it will work for very limited number of
> > > clients, they're not intended as AP chips. If you want something
> > > to
> > > work as an AP, I recommend you choose an AP chip.
> > 
> > We do have wiphy::max_ap_assoc_sta, but I see only ath10k, qtnfmac
> > and
> > rsi_91x setting it. I wish all drivers would use that.
> > 
> >  * @max_ap_assoc_sta: maximum number of associated stations
> > supported in AP mode
> >  * (including P2P GO) or 0 to indicate no such limit is advertised.
> > The
> >  * driver is allowed to advertise a theoretical limit that it can
> > reach in
> >  * some cases, but may not always reach.
> 
> Cool, I hadn't noticed this before.  I'll add a patch to iwlwifi to
> add it.

Actually this is not so straightforward, because every time we add a
p2p vif, we lose one more station.  So the max_ap_assoc_sta value must
be dynamic (or we can state the theoretical lowest number to start
with, which would not be very nice).

I don't think this feature is worth the trouble, so I'll skip it for
now.

--
Cheers,
Luca.