linux-kernel - Re: [PATCH 1/3] wifi: mt76: mt7915: remove VHT160 capability on MT7915

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Date:   Thu, 21 Sep 2023 09:19:58 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Oleksandr Natalenko <oleksandr@...alenko.name>
Cc:     linux-wireless@...r.kernel.org, Felix Fietkau <nbd@....name>,
        Sasha Levin <sashal@...nel.org>, stable@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] wifi: mt76: mt7915: remove VHT160 capability on
 MT7915

On Thu, Sep 21, 2023 at 07:02:41AM +0200, Oleksandr Natalenko wrote:
> Hello Felix.
> 
> On středa 26. července 2023 11:17:02 CEST Felix Fietkau wrote:
> > The IEEE80211_VHT_CAP_EXT_NSS_BW value already indicates support for half-NSS
> > 160 MHz support, so it is wrong to also advertise full 160 MHz support.
> > 
> > Fixes: c2f73eacee3b ("wifi: mt76: mt7915: add back 160MHz channel width support for MT7915")
> > Signed-off-by: Felix Fietkau <nbd@....name>
> > ---
> >  drivers/net/wireless/mediatek/mt76/mt7915/init.c | 1 -
> >  1 file changed, 1 deletion(-)
> > 
> > diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/init.c b/drivers/net/wireless/mediatek/mt76/mt7915/init.c
> > index ee976657bfc3..78552f10b377 100644
> > --- a/drivers/net/wireless/mediatek/mt76/mt7915/init.c
> > +++ b/drivers/net/wireless/mediatek/mt76/mt7915/init.c
> > @@ -414,7 +414,6 @@ mt7915_init_wiphy(struct mt7915_phy *phy)
> >  			if (!dev->dbdc_support)
> >  				vht_cap->cap |=
> >  					IEEE80211_VHT_CAP_SHORT_GI_160 |
> > -					IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ |
> >  					FIELD_PREP(IEEE80211_VHT_CAP_EXT_NSS_BW_MASK, 1);
> >  		} else {
> >  			vht_cap->cap |=
> > 
> 
> For some reason this got backported into the stable kernel:
> 
> ```
> $ git log --oneline v6.5.2..v6.5.4 -- drivers/net/wireless/mediatek/mt76/mt7915/
> c43017fbebcc3 wifi: mt76: mt7915: fix power-limits while chan_switch
> edb1afe042c74 wifi: mt76: mt7915: fix tlv length of mt7915_mcu_get_chan_mib_info
> 9ec0dec0baea3 wifi: mt76: mt7915: remove VHT160 capability on MT7915
> 0e61f73e6ebc0 wifi: mt76: mt7915: fix capabilities in non-AP mode
> 6bce28ce28390 wifi: mt76: mt7915: fix command timeout in AP stop period
> 7af917d4864c6 wifi: mt76: mt7915: rework tx bytes counting when WED is active
> feae00c6468ce wifi: mt76: mt7915: rework tx packets counting when WED is active
> 70bbcc4ad6544 wifi: mt76: mt7915: fix background radar event being blocked
> ```
> 
> and this broke my mt7915-based AP.
> 
> However, if I remove `[VT160]` capability from the hostapd config, things go back to normal. It does seem that 160 MHz still works even.
> 
> Is this expected?

Is your device also broken in 6.6-rc2?

thanks,

greg k-h