[PATCH] mt76: fix monitor rx FCS error in DFS channel

[Lorenzo Bianconi]

> Hi Lore,
> 
> On Wed, 2022-03-16 at 16:15 +0100, Lorenzo Bianconi wrote:
> > > From: Deren Wu <deren.wu at mediatek.com>
> > > 
> > > When setup monitor mode in DFS channel, mt76 send CH_SWITCH_DFS to
> > > fw for channel config. This would cause rx performance bad while
> > > monitoring frames. Settings CH_SWITCH_NORMAL in monitor mode would
> > > get the same performance as normal channels.
> > 
> > Hi Deren,
> > 
> > > 
> > > Reviewed-by: Shayne Chen <shayne.chen at mediatek.com>
> > > Signed-off-by: Deren Wu <deren.wu at mediatek.com>
> > > ---
> > >  drivers/net/wireless/mediatek/mt76/mt7615/mcu.c | 3 ++-
> > >  drivers/net/wireless/mediatek/mt76/mt7915/mcu.c | 3 ++-
> > >  drivers/net/wireless/mediatek/mt76/mt7921/mcu.c | 3 ++-
> > >  3 files changed, 6 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c
> > > b/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c
> > > index 390add3144c2..97e2a85cb728 100644
> > > --- a/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c
> > > +++ b/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c
> > > @@ -2151,7 +2151,8 @@ int mt7615_mcu_set_chan_info(struct
> > > mt7615_phy *phy, int cmd)
> > >  		.center_chan2 = ieee80211_frequency_to_channel(freq2),
> > >  	};
> > >  
> > > -	if (cmd == MCU_EXT_CMD(SET_RX_PATH))
> > > +	if (cmd == MCU_EXT_CMD(SET_RX_PATH) ||
> > > +	    dev->mt76.hw->conf.flags & IEEE80211_CONF_MONITOR)
> > 
> > is this patch compliant with 802.11h DFS standard?
> 
> Monitor mode would not tx packets and still follow standard. We will
> keep tracking this point to avoid violations.

Hi Deren,

this IEEE80211_CONF_MONITOR flags indicates there is a monitor interface,
not it is the only one so we can have multiple vifs on the device
(e.g. AP + monitor). I was wondering if CH_SWITCH_SCAN_BYPASS_DPD is used
to avoid transmitting packets during chip calibration on DFS channels.

Regards,
Lorenzo

> 
> 
> Regards,
> Deren
> 
> 
> > 
> > Regards,
> > Lorenzo
> > 
> > >  		req.switch_reason = CH_SWITCH_NORMAL;
> > >  	else if (phy->mt76->hw->conf.flags & IEEE80211_CONF_OFFCHANNEL)
> > >  		req.switch_reason = CH_SWITCH_SCAN_BYPASS_DPD;
> > > diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
> > > b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
> > > index 10dc4bf5adec..c56d48342aaf 100644
> > > --- a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
> > > +++ b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
> > > @@ -2833,7 +2833,8 @@ int mt7915_mcu_set_chan_info(struct
> > > mt7915_phy *phy, int cmd)
> > >  	}
> > >  #endif
> > >  
> > > -	if (cmd == MCU_EXT_CMD(SET_RX_PATH))
> > > +	if (cmd == MCU_EXT_CMD(SET_RX_PATH) ||
> > > +	    dev->mt76.hw->conf.flags & IEEE80211_CONF_MONITOR)
> > >  		req.switch_reason = CH_SWITCH_NORMAL;
> > >  	else if (phy->mt76->hw->conf.flags & IEEE80211_CONF_OFFCHANNEL)
> > >  		req.switch_reason = CH_SWITCH_SCAN_BYPASS_DPD;
> > > diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
> > > b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
> > > index 5ef8b24f0ab3..da2be050ed7c 100644
> > > --- a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
> > > +++ b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
> > > @@ -863,7 +863,8 @@ int mt7921_mcu_set_chan_info(struct mt7921_phy
> > > *phy, int cmd)
> > >  	else
> > >  		req.channel_band = chandef->chan->band;
> > >  
> > > -	if (cmd == MCU_EXT_CMD(SET_RX_PATH))
> > > +	if (cmd == MCU_EXT_CMD(SET_RX_PATH) ||
> > > +	    dev->mt76.hw->conf.flags & IEEE80211_CONF_MONITOR)
> > >  		req.switch_reason = CH_SWITCH_NORMAL;
> > >  	else if (dev->mt76.hw->conf.flags & IEEE80211_CONF_OFFCHANNEL)
> > >  		req.switch_reason = CH_SWITCH_SCAN_BYPASS_DPD;
> > > -- 
> > > 2.18.0
> > > 
> 
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