Re: [PATCH 4/6] mt76: mt7615: unlock dfs bands

[Ryder Lee <ryder.lee@mediatek.com>]

On Mon, 2019-07-01 at 10:59 +0300, Kalle Valo wrote:
> Lorenzo Bianconi <lorenzo.bianconi@redhat.com> writes:
> 
> >>
> >> Lorenzo Bianconi <lorenzo@kernel.org> writes:
> >>
> >> > Unlock dfs channels since now mt7615 driver supports radar detection
> >> >
> >> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> >> > ---
> >> >  drivers/net/wireless/mediatek/mt76/mt7615/init.c | 6 ++++++
> >> >  1 file changed, 6 insertions(+)
> >> >
> >> > diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/init.c b/drivers/net/wireless/mediatek/mt76/mt7615/init.c
> >> > index 5dc4cced5789..6d336d82cafe 100644
> >> > --- a/drivers/net/wireless/mediatek/mt76/mt7615/init.c
> >> > +++ b/drivers/net/wireless/mediatek/mt76/mt7615/init.c
> >> > @@ -152,6 +152,12 @@ static const struct ieee80211_iface_combination if_comb[] = {
> >> >               .max_interfaces = 4,
> >> >               .num_different_channels = 1,
> >> >               .beacon_int_infra_match = true,
> >> > +             .radar_detect_widths = BIT(NL80211_CHAN_WIDTH_20_NOHT) |
> >> > +                                    BIT(NL80211_CHAN_WIDTH_20) |
> >> > +                                    BIT(NL80211_CHAN_WIDTH_40) |
> >> > +                                    BIT(NL80211_CHAN_WIDTH_80) |
> >> > +                                    BIT(NL80211_CHAN_WIDTH_160) |
> >> > +                                    BIT(NL80211_CHAN_WIDTH_80P80),
> >>
> >> Isn't it questionable to enable these without any testing on real
> >> hardware? Getting DFS to work correctly is hard so I'm very suspicious
> >> about this.
> >>
> >> --
> >> Kalle Valo
> >
> > Hi Kalle,
> >
> > unfortunately at the moment I am not able to run any tests with a real
> > signal generator so I just ported the code from vendor sdk.
> > I am pretty confident it works since the radar pattern detection is
> > done in fw/hw so I guess it has been already tested in the vendor sdk
> 
> DFS is really tricky to get it working right, so I'm not easily
> convinced :)
> 
> > but we can postpone this patch and apply just the rest of the series
> > until we have some test results.
> 
> Yeah, I think it would be best to drop this patch so that DFS is not
> enabled by default and apply this patch only after positive test
> results.
> 

That's why I suggested Lorenzo to add this one - "[6/6] mt76: mt7615:
add radar pattern test knob to debugfs"

We can feed radar pattern through debugfs to test if a pattern is
detected as radar pattern or not and verify the fw radar detection
algorithm.

In this format:
RadarPulsePattern="3680128-2-245;3683878-2-245;3687628-2-245;3691378-2-245;3695128-2-245;3698878-2-245;3702628-2-245;3706378-2-245;3710128-2-245;3713878-2-245"

As for testing it on 'real hardware' I need to take some other time to
borrow equipment.

Ryder