[RFC PATCH] wifi: rt2x00: use VCO_IC 0x2 for RF3053 on 2.4 GHz

[RFC PATCH] wifi: rt2x00: use VCO_IC 0x2 for RF3053 on 2.4 GHz

[Ho Jie Feng]

Using the 0x1, the VCO calibration result is 0x7f on channels 6
and below. Using 0x2 fixes it.

Hardware: Netgear WNDA4100 (USB 0846:9013, RT3593 rev 0402, RF3053)

Signed-off-by: Ho Jie Feng <hjf3108@gmail.com>
---
RFC for this since I am not sure if it is a generic fix, since the
vendor driver also doesn't use VCO_IC=0x2.
Is this also a known issue?

Testing on different hardware would be appreciated.

 drivers/net/wireless/ralink/rt2x00/rt2800lib.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ralink/rt2x00/rt2800lib.c b/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
index 2e2e382b62475..4a44a0222210d 100644
--- a/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
+++ b/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
@@ -2979,7 +2979,7 @@ static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
 
 	rfcsr = rt2800_rfcsr_read(rt2x00dev, 6);
 	if (rf->channel >= 1 && rf->channel <= 14)
-		rt2x00_set_field8(&rfcsr, RFCSR6_VCO_IC, 1);
+		rt2x00_set_field8(&rfcsr, RFCSR6_VCO_IC, 2);
 	else if (rf->channel >= 36 && rf->channel <= 64)
 		rt2x00_set_field8(&rfcsr, RFCSR6_VCO_IC, 2);
 	else if (rf->channel >= 100 && rf->channel <= 128)

base-commit: af32da41b0327b9c6a37856ba82b6760d6c8d10e
-- 
2.55.0

Re: [RFC PATCH] wifi: rt2x00: use VCO_IC 0x2 for RF3053 on 2.4 GHz

[Stanislaw Gruszka]

Hi

On Mon, Oct 12, 2026 at 09:37:27PM +0800, Ho Jie Feng wrote:
> Using the 0x1, the VCO calibration result is 0x7f on channels 6
> and below. Using 0x2 fixes it.
>
> Hardware: Netgear WNDA4100 (USB 0846:9013, RT3593 rev 0402, RF3053)
> 
> Signed-off-by: Ho Jie Feng <hjf3108@gmail.com>
> ---
> RFC for this since I am not sure if it is a generic fix, since the
> vendor driver also doesn't use VCO_IC=0x2.
> Is this also a known issue?

Could you elaborate what is the issue and what you mean by
"VCO calibration result is 0x7f" ?

Regards
Stanislaw

> Testing on different hardware would be appreciated.
> 
>  drivers/net/wireless/ralink/rt2x00/rt2800lib.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/ralink/rt2x00/rt2800lib.c b/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
> index 2e2e382b62475..4a44a0222210d 100644
> --- a/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
> +++ b/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
> @@ -2979,7 +2979,7 @@ static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
>  
>  	rfcsr = rt2800_rfcsr_read(rt2x00dev, 6);
>  	if (rf->channel >= 1 && rf->channel <= 14)
> -		rt2x00_set_field8(&rfcsr, RFCSR6_VCO_IC, 1);
> +		rt2x00_set_field8(&rfcsr, RFCSR6_VCO_IC, 2);
>  	else if (rf->channel >= 36 && rf->channel <= 64)
>  		rt2x00_set_field8(&rfcsr, RFCSR6_VCO_IC, 2);
>  	else if (rf->channel >= 100 && rf->channel <= 128)
> 
> base-commit: af32da41b0327b9c6a37856ba82b6760d6c8d10e
> -- 
> 2.55.0
> 

Re: [RFC PATCH] wifi: rt2x00: use VCO_IC 0x2 for RF3053 on 2.4 GHz

[Jie Feng]

On Tue, 13 Oct 2026 at 18:23, Stanislaw Gruszka <stf_xl@wp.pl> wrote:
>
> Hi
>
> On Mon, Oct 12, 2026 at 09:37:27PM +0800, Ho Jie Feng wrote:
> > Using the 0x1, the VCO calibration result is 0x7f on channels 6
> > and below. Using 0x2 fixes it.
> >
> > Hardware: Netgear WNDA4100 (USB 0846:9013, RT3593 rev 0402, RF3053)
> >
> > Signed-off-by: Ho Jie Feng <hjf3108@gmail.com>
> > ---
> > RFC for this since I am not sure if it is a generic fix, since the
> > vendor driver also doesn't use VCO_IC=0x2.
> > Is this also a known issue?
>
> Could you elaborate what is the issue and what you mean by
> "VCO calibration result is 0x7f" ?'
I had accidentally left the description out, sorry about that.

The adapter doesn't work on the lower channels in 2.4GHz,
channels 8 and below. This looked like an issue with
the PLL or something after debugging.

By tuning to channels 1-12 and using the debugfs to dump the
RFCSR registers, RFCSR4 is always 0x7f on the failing channels
consistently. Since there is code to switch RFCSR6 based on
channel, I tried the same as the 5GHz code to switch RFCSR6=0x2
for lower channels and it worked on all the channels surprisingly.

Due to the behaviour of RFCSR4, I think it is a VCO calibration
result since it seems to change after enabling the calibration.

I could not find any mention of this issue elsewhere, and suspect
either this hardware has very few Linux users or my hardware
is special in some way, so I can't guarantee that setting
it to 0x2 will work with another device even if it is the
same WNDA4100 model and chipset, so some testing would
be appreciated.

> Regards
> Stanislaw
>
> > Testing on different hardware would be appreciated.
> >
> >  drivers/net/wireless/ralink/rt2x00/rt2800lib.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/wireless/ralink/rt2x00/rt2800lib.c b/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
> > index 2e2e382b62475..4a44a0222210d 100644
> > --- a/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
> > +++ b/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
> > @@ -2979,7 +2979,7 @@ static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
> >
> >       rfcsr = rt2800_rfcsr_read(rt2x00dev, 6);
> >       if (rf->channel >= 1 && rf->channel <= 14)
> > -             rt2x00_set_field8(&rfcsr, RFCSR6_VCO_IC, 1);
> > +             rt2x00_set_field8(&rfcsr, RFCSR6_VCO_IC, 2);
> >       else if (rf->channel >= 36 && rf->channel <= 64)
> >               rt2x00_set_field8(&rfcsr, RFCSR6_VCO_IC, 2);
> >       else if (rf->channel >= 100 && rf->channel <= 128)
> >
> > base-commit: af32da41b0327b9c6a37856ba82b6760d6c8d10e
> > --
> > 2.55.0
> >

Re: [RFC PATCH] wifi: rt2x00: use VCO_IC 0x2 for RF3053 on 2.4 GHz

[Stanislaw Gruszka]

On Tue, Oct 13, 2026 at 08:49:44PM +0800, Jie Feng wrote:
> On Tue, 13 Oct 2026 at 18:23, Stanislaw Gruszka <stf_xl@wp.pl> wrote:
> >
> > Hi
> >
> > On Mon, Oct 12, 2026 at 09:37:27PM +0800, Ho Jie Feng wrote:
> > > Using the 0x1, the VCO calibration result is 0x7f on channels 6
> > > and below. Using 0x2 fixes it.
> > >
> > > Hardware: Netgear WNDA4100 (USB 0846:9013, RT3593 rev 0402, RF3053)
> > >
> > > Signed-off-by: Ho Jie Feng <hjf3108@gmail.com>
> > > ---
> > > RFC for this since I am not sure if it is a generic fix, since the
> > > vendor driver also doesn't use VCO_IC=0x2.

I looked at vendor driver it does not set VCO_IC=0x2 when switch 
a channel. However it does it after wake up from suspend:
https://github.com/ashaffer/rt3573sta/blob/09b80e6290769c53736dc09c5ae9025e15bfbe69/chips/rt3593.c#L194

This function: RT3593ReverseRFSleepModeSetup seams to be partially
the same what NICInitRT3593RFRegisters does. 

Also NICInitRT3593RFRegisters it's different from
rt2800_init_rfcsr_3593() i.e. it set RF_R02 before GPIO_SWITCH.

Could you check if modifying rt2800_init_rfcsr_3593() 
to be more the same with both NICInitRT3593RFRegistersr and
RT3593ReverseRFSleepModeSetup (regarding RF_R06 change)
solve the problem?

> > > Is this also a known issue?
I didn't knew about it.

> > Could you elaborate what is the issue and what you mean by
> > "VCO calibration result is 0x7f" ?'
> I had accidentally left the description out, sorry about that.
No problem.

> The adapter doesn't work on the lower channels in 2.4GHz,
> channels 8 and below. This looked like an issue with
> the PLL or something after debugging.
> 
> By tuning to channels 1-12 and using the debugfs to dump the
> RFCSR registers, RFCSR4 is always 0x7f on the failing channels
> consistently. Since there is code to switch RFCSR6 based on
> channel, I tried the same as the 5GHz code to switch RFCSR6=0x2
> for lower channels and it worked on all the channels surprisingly.
> 
> Due to the behaviour of RFCSR4, I think it is a VCO calibration
> result since it seems to change after enabling the calibration.
> 
> I could not find any mention of this issue elsewhere, and suspect
> either this hardware has very few Linux users or my hardware
> is special in some way, so I can't guarantee that setting
> it to 0x2 will work with another device even if it is the
> same WNDA4100 model and chipset, so some testing would
> be appreciated.
I do not have RT3573/RT3593 device by myself and ordinary users
do not read linux-wireless mailing list, so we have rather little
chance to get more test coverage here.

Anyways, if init change that would make rt2800_init_rfcsr_3593()
more like vendor driver do not fix the problem, it's ok to modify
rt2800_config_channel_rf3053(). 

If we want to be more safe with the change, we can limit it with
rt2x00_rt_rev() using 'rev' of your tested device.

Regards
Stanislaw

Re: [RFC PATCH] wifi: rt2x00: use VCO_IC 0x2 for RF3053 on 2.4 GHz

[Jie Feng]

On Wed, 14 Oct 2026 at 16:31, Stanislaw Gruszka <stf_xl@wp.pl> wrote:
> > > > RFC for this since I am not sure if it is a generic fix, since the
> > > > vendor driver also doesn't use VCO_IC=0x2.
>
> I looked at vendor driver it does not set VCO_IC=0x2 when switch
> a channel. However it does it after wake up from suspend:
> https://github.com/ashaffer/rt3573sta/blob/09b80e6290769c53736dc09c5ae9025e15bfbe69/chips/rt3593.c#L194
>
> This function: RT3593ReverseRFSleepModeSetup seams to be partially
> the same what NICInitRT3593RFRegisters does.
>
> Also NICInitRT3593RFRegisters it's different from
> rt2800_init_rfcsr_3593() i.e. it set RF_R02 before GPIO_SWITCH.
>
> Could you check if modifying rt2800_init_rfcsr_3593()
> to be more the same with both NICInitRT3593RFRegistersr and
> RT3593ReverseRFSleepModeSetup (regarding RF_R06 change)
> solve the problem?
It didn't solve the problem.

> > The adapter doesn't work on the lower channels in 2.4GHz,
> > channels 8 and below. This looked like an issue with
> > the PLL or something after debugging.
> >
> > By tuning to channels 1-12 and using the debugfs to dump the
> > RFCSR registers, RFCSR4 is always 0x7f on the failing channels
> > consistently. Since there is code to switch RFCSR6 based on
> > channel, I tried the same as the 5GHz code to switch RFCSR6=0x2
> > for lower channels and it worked on all the channels surprisingly.
> >
> > Due to the behaviour of RFCSR4, I think it is a VCO calibration
> > result since it seems to change after enabling the calibration.
> >
> > I could not find any mention of this issue elsewhere, and suspect
> > either this hardware has very few Linux users or my hardware
> > is special in some way, so I can't guarantee that setting
> > it to 0x2 will work with another device even if it is the
> > same WNDA4100 model and chipset, so some testing would
> > be appreciated.
> I do not have RT3573/RT3593 device by myself and ordinary users
> do not read linux-wireless mailing list, so we have rather little
> chance to get more test coverage here.
>
> Anyways, if init change that would make rt2800_init_rfcsr_3593()
> more like vendor driver do not fix the problem, it's ok to modify
> rt2800_config_channel_rf3053().
>
> If we want to be more safe with the change, we can limit it with
> rt2x00_rt_rev() using 'rev' of your tested device.
My concern is that it is just my specific device being at fault here.
It also seems to have an issue where the TX looks to be much weaker
than normal.