Re: [PATCH wireless 4/4] wifi: mt76: mt7925: fix RCPI chain 3 mask in sta_poll RSSI extraction

[Joshua Klinesmith]

On 4/7/26 11:25, Ben Greear wrote:
> How much of this is AI driven?  As far as I know, mt7925 is a 2x2 chipset
> at max.  So while the patch may be correct, it may also not matter in practice
> and at least may not need to be backported into stable.

Hi Ben,

Please accept my apologies. You are correct that the mt7925 is a 2x2
chipset, so this does not have a practical impact and should not have
been tagged for stable. I did not read the documentation in its
entirety before submitting, and that is on me.

I will be much more careful and diligent with testing and review going forward.

Thanks for the feedback.

Joshua


On Tue, Apr 7, 2026 at 11:25 AM Ben Greear <greearb@xxxxxxxxxxxxxxx> wrote:
>
> On 4/6/26 16:47, Joshua Klinesmith wrote:
> > The fourth receive chain RCPI uses GENMASK(31, 14), an 18-bit mask
> > spanning bits 14-31. It should be GENMASK(31, 24), an 8-bit mask
> > for the fourth byte, consistent with the other three chains and
> > with the RCPI3 definitions used elsewhere in the driver
> > (MT_PRXV_RCPI3 and MT_TXS7_F0_RCPI_3 both use GENMASK(31, 24)).
>
> Hello Joshua,
>
> How much of this is AI driven?  As far as I know, mt7925 is a 2x2 chipset
> at max.  So while the patch may be correct, it may also not matter in practice
> and at least may not need to be backported into stable.  If it is a minor
> cleanup that doesn't actually matter, that should be described more clearly
> in the commit message?
>
> Some of your patches are touching tricky parts of the code and making
> subtle comparisons against how the vendor's driver is written.  How well has
> this been tested and reviewed by a knowledgeable human in general?
>
> Thanks,
> Ben
>
> >
> > On devices with fewer than 4 antenna chains, the corrupted value
> > is masked out by antenna_mask in mt76_rx_signal(). On 4-chain
> > devices, this produces incorrect ACK signal strength readings.
> >
> > Fixes: c948b5da6bbe ("wifi: mt76: mt7925: add Mediatek Wi-Fi7 driver for mt7925 chips")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Joshua Klinesmith <joshuaklinesmith@xxxxxxxxx>
> > ---
> >   drivers/net/wireless/mediatek/mt76/mt7925/mac.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/mac.c b/drivers/net/wireless/mediatek/mt76/mt7925/mac.c
> > index 6334019249..85e91ca84f 100644
> > --- a/drivers/net/wireless/mediatek/mt76/mt7925/mac.c
> > +++ b/drivers/net/wireless/mediatek/mt76/mt7925/mac.c
> > @@ -144,7 +144,7 @@ static void mt7925_mac_sta_poll(struct mt792x_dev *dev)
> >               rssi[0] = to_rssi(GENMASK(7, 0), val);
> >               rssi[1] = to_rssi(GENMASK(15, 8), val);
> >               rssi[2] = to_rssi(GENMASK(23, 16), val);
> > -             rssi[3] = to_rssi(GENMASK(31, 14), val);
> > +             rssi[3] = to_rssi(GENMASK(31, 24), val);
> >
> >               mlink->ack_signal =
> >                       mt76_rx_signal(msta->vif->phy->mt76->antenna_mask, rssi);
>
> --
> Ben Greear <greearb@xxxxxxxxxxxxxxx>
> Candela Technologies Inc  http://www.candelatech.com
>