diff mbox

[3/3] ath9k: add noise floor override option

Message ID 20170316151337.24163-4-sw@simonwunderlich.de (mailing list archive)
State Not Applicable
Delegated to: Kalle Valo
Headers show

Commit Message

Simon Wunderlich March 16, 2017, 3:13 p.m. UTC
Introduce a debugfs option to manually override the noise floor,
ignoring the automatically tuned noise floor of the driver/hw.

In my tests with a AR9580 based module and a tx99 5 MHz interferer,
I could tune the noisefloor to -95 dBm or above to allow communication
again. The automatic noise floor calibration sometimes could adapt to
the situation as well, but not reliably and permanently.

I would consider this "feature" experimental and interesting for people
debugging the noise floor calibration or other effects of the hardware.

Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fit.fraunhofer.de>
---
 drivers/net/wireless/ath/ath9k/calib.c |  5 ++-
 drivers/net/wireless/ath/ath9k/debug.c | 62 ++++++++++++++++++++++++++++++++++
 drivers/net/wireless/ath/ath9k/hw.h    |  1 +
 3 files changed, 67 insertions(+), 1 deletion(-)

Comments

Janusz.Dziedzic@tieto.com March 17, 2017, 8:48 a.m. UTC | #1
On 16 March 2017 at 16:13, Simon Wunderlich <sw@simonwunderlich.de> wrote:
> Introduce a debugfs option to manually override the noise floor,
> ignoring the automatically tuned noise floor of the driver/hw.
>
> In my tests with a AR9580 based module and a tx99 5 MHz interferer,
> I could tune the noisefloor to -95 dBm or above to allow communication
> again. The automatic noise floor calibration sometimes could adapt to
> the situation as well, but not reliably and permanently.
>
> I would consider this "feature" experimental and interesting for people
> debugging the noise floor calibration or other effects of the hardware.
>
> Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
> Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fit.fraunhofer.de>
> ---
>  drivers/net/wireless/ath/ath9k/calib.c |  5 ++-
>  drivers/net/wireless/ath/ath9k/debug.c | 62 ++++++++++++++++++++++++++++++++++
>  drivers/net/wireless/ath/ath9k/hw.h    |  1 +
>  3 files changed, 67 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/ath/ath9k/calib.c b/drivers/net/wireless/ath/ath9k/calib.c
> index 0f71146b781d..13ab6bc46775 100644
> --- a/drivers/net/wireless/ath/ath9k/calib.c
> +++ b/drivers/net/wireless/ath/ath9k/calib.c
> @@ -254,7 +254,9 @@ int ath9k_hw_loadnf(struct ath_hw *ah, struct ath9k_channel *chan)
>                         if ((i >= AR5416_MAX_CHAINS) && !IS_CHAN_HT40(chan))
>                                 continue;
>
> -                       if (h)
> +                       if (ah->nf_override)
> +                               nfval = ah->nf_override;
> +                       else if (h)
>                                 nfval = h[i].privNF;
>                         else
>                                 nfval = default_nf;
> @@ -348,6 +350,7 @@ int ath9k_hw_loadnf(struct ath_hw *ah, struct ath9k_channel *chan)
>
>         return 0;
>  }
> +EXPORT_SYMBOL(ath9k_hw_loadnf);
>
>
>  static void ath9k_hw_nf_sanitize(struct ath_hw *ah, s16 *nf)
> diff --git a/drivers/net/wireless/ath/ath9k/debug.c b/drivers/net/wireless/ath/ath9k/debug.c
> index 43930c336987..2e64977a8ab6 100644
> --- a/drivers/net/wireless/ath/ath9k/debug.c
> +++ b/drivers/net/wireless/ath/ath9k/debug.c
> @@ -1191,6 +1191,65 @@ static const struct file_operations fops_tpc = {
>         .llseek = default_llseek,
>  };
>
> +static ssize_t read_file_nf_override(struct file *file,
> +                                    char __user *user_buf,
> +                                    size_t count, loff_t *ppos)
> +{
> +       struct ath_softc *sc = file->private_data;
> +       struct ath_hw *ah = sc->sc_ah;
> +       char buf[32];
> +       unsigned int len;
> +
> +       if (ah->nf_override == 0)
> +               len = sprintf(buf, "off\n");
> +       else
> +               len = sprintf(buf, "%d\n", ah->nf_override);
> +
> +       return simple_read_from_buffer(user_buf, count, ppos, buf, len);
> +}
> +
> +static ssize_t write_file_nf_override(struct file *file,
> +                                     const char __user *user_buf,
> +                                     size_t count, loff_t *ppos)
> +{
> +       struct ath_softc *sc = file->private_data;
> +       struct ath_hw *ah = sc->sc_ah;
> +       long val;
> +       char buf[32];
> +       ssize_t len;
> +
> +       len = min(count, sizeof(buf) - 1);
> +       if (copy_from_user(buf, user_buf, len))
> +               return -EFAULT;
> +
> +       buf[len] = '\0';
> +       if (strncmp("off", buf, 3) == 0)
> +               val = 0;
> +       else if (kstrtol(buf, 0, &val))
> +               return -EINVAL;
> +
> +       if (val > 0)
> +               return -EINVAL;
> +
> +       if (val < -120)
> +               return -EINVAL;
> +
> +       ah->nf_override = val;
> +
> +       if (ah->curchan)
> +               ath9k_hw_loadnf(ah, ah->curchan);
> +
> +       return count;
> +}
> +
> +static const struct file_operations fops_nf_override = {
> +       .read = read_file_nf_override,
> +       .write = write_file_nf_override,
> +       .open = simple_open,
> +       .owner = THIS_MODULE,
> +       .llseek = default_llseek,
> +};
> +
>  /* Ethtool support for get-stats */
>
>  #define AMKSTR(nm) #nm "_BE", #nm "_BK", #nm "_VI", #nm "_VO"
> @@ -1402,5 +1461,8 @@ int ath9k_init_debug(struct ath_hw *ah)
>         debugfs_create_u16("airtime_flags", S_IRUSR | S_IWUSR,
>                            sc->debug.debugfs_phy, &sc->airtime_flags);
>
> +       debugfs_create_file("nf_override", S_IRUSR | S_IWUSR,
> +                           sc->debug.debugfs_phy, sc, &fops_nf_override);
> +

Why not simply:
        debugfs_create_u32("nf_override", S_IRUSR|S_IWUSR ,
sc->debug.debugfs_phy,
                          &ah->nf_override);

One line patch :)

>         return 0;
>  }
> diff --git a/drivers/net/wireless/ath/ath9k/hw.h b/drivers/net/wireless/ath/ath9k/hw.h
> index 496e3cd1b509..eba478f052b9 100644
> --- a/drivers/net/wireless/ath/ath9k/hw.h
> +++ b/drivers/net/wireless/ath/ath9k/hw.h
> @@ -803,6 +803,7 @@ struct ath_hw {
>         u32 rfkill_gpio;
>         u32 rfkill_polarity;
>         u32 ah_flags;
> +       s16 nf_override;
>
>         bool reset_power_on;
>         bool htc_reset_init;
> --
> 2.11.0
>
>
> _______________________________________________
> ath10k mailing list
> ath10k@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/ath10k
Simon Wunderlich March 17, 2017, 8:55 a.m. UTC | #2
On Friday, March 17, 2017 9:48:07 AM CET Janusz Dziedzic wrote:
> On 16 March 2017 at 16:13, Simon Wunderlich <sw@simonwunderlich.de> wrote:
> > Introduce a debugfs option to manually override the noise floor,
> > ignoring the automatically tuned noise floor of the driver/hw.
> > 
> > In my tests with a AR9580 based module and a tx99 5 MHz interferer,
> > I could tune the noisefloor to -95 dBm or above to allow communication
> > again. The automatic noise floor calibration sometimes could adapt to
> > the situation as well, but not reliably and permanently.
> > 
> > I would consider this "feature" experimental and interesting for people
> > debugging the noise floor calibration or other effects of the hardware.
> > 
> > Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
> > Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fit.fraunhofer.de>
> > ---
> > 
> >  drivers/net/wireless/ath/ath9k/calib.c |  5 ++-
> >  drivers/net/wireless/ath/ath9k/debug.c | 62
> >  ++++++++++++++++++++++++++++++++++ drivers/net/wireless/ath/ath9k/hw.h  
> >   |  1 +
> >  3 files changed, 67 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/wireless/ath/ath9k/calib.c
> > b/drivers/net/wireless/ath/ath9k/calib.c index 0f71146b781d..13ab6bc46775
> > 100644
> > --- a/drivers/net/wireless/ath/ath9k/calib.c
> > +++ b/drivers/net/wireless/ath/ath9k/calib.c
> > @@ -254,7 +254,9 @@ int ath9k_hw_loadnf(struct ath_hw *ah, struct
> > ath9k_channel *chan)> 
> >                         if ((i >= AR5416_MAX_CHAINS) &&
> >                         !IS_CHAN_HT40(chan))
> >                         
> >                                 continue;
> > 
> > -                       if (h)
> > +                       if (ah->nf_override)
> > +                               nfval = ah->nf_override;
> > +                       else if (h)
> > 
> >                                 nfval = h[i].privNF;
> >                         
> >                         else
> >                         
> >                                 nfval = default_nf;
> > 
> > @@ -348,6 +350,7 @@ int ath9k_hw_loadnf(struct ath_hw *ah, struct
> > ath9k_channel *chan)> 
> >         return 0;
> >  
> >  }
> > 
> > +EXPORT_SYMBOL(ath9k_hw_loadnf);
> > 
> >  static void ath9k_hw_nf_sanitize(struct ath_hw *ah, s16 *nf)
> > 
> > diff --git a/drivers/net/wireless/ath/ath9k/debug.c
> > b/drivers/net/wireless/ath/ath9k/debug.c index 43930c336987..2e64977a8ab6
> > 100644
> > --- a/drivers/net/wireless/ath/ath9k/debug.c
> > +++ b/drivers/net/wireless/ath/ath9k/debug.c
> > @@ -1191,6 +1191,65 @@ static const struct file_operations fops_tpc = {
> > 
> >         .llseek = default_llseek,
> >  
> >  };
> > 
> > +static ssize_t read_file_nf_override(struct file *file,
> > +                                    char __user *user_buf,
> > +                                    size_t count, loff_t *ppos)
> > +{
> > +       struct ath_softc *sc = file->private_data;
> > +       struct ath_hw *ah = sc->sc_ah;
> > +       char buf[32];
> > +       unsigned int len;
> > +
> > +       if (ah->nf_override == 0)
> > +               len = sprintf(buf, "off\n");
> > +       else
> > +               len = sprintf(buf, "%d\n", ah->nf_override);
> > +
> > +       return simple_read_from_buffer(user_buf, count, ppos, buf, len);
> > +}
> > +
> > +static ssize_t write_file_nf_override(struct file *file,
> > +                                     const char __user *user_buf,
> > +                                     size_t count, loff_t *ppos)
> > +{
> > +       struct ath_softc *sc = file->private_data;
> > +       struct ath_hw *ah = sc->sc_ah;
> > +       long val;
> > +       char buf[32];
> > +       ssize_t len;
> > +
> > +       len = min(count, sizeof(buf) - 1);
> > +       if (copy_from_user(buf, user_buf, len))
> > +               return -EFAULT;
> > +
> > +       buf[len] = '\0';
> > +       if (strncmp("off", buf, 3) == 0)
> > +               val = 0;
> > +       else if (kstrtol(buf, 0, &val))
> > +               return -EINVAL;
> > +
> > +       if (val > 0)
> > +               return -EINVAL;
> > +
> > +       if (val < -120)
> > +               return -EINVAL;
> > +
> > +       ah->nf_override = val;
> > +
> > +       if (ah->curchan)
> > +               ath9k_hw_loadnf(ah, ah->curchan);
> > +
> > +       return count;
> > +}
> > +
> > +static const struct file_operations fops_nf_override = {
> > +       .read = read_file_nf_override,
> > +       .write = write_file_nf_override,
> > +       .open = simple_open,
> > +       .owner = THIS_MODULE,
> > +       .llseek = default_llseek,
> > +};
> > +
> > 
> >  /* Ethtool support for get-stats */
> >  
> >  #define AMKSTR(nm) #nm "_BE", #nm "_BK", #nm "_VI", #nm "_VO"
> > 
> > @@ -1402,5 +1461,8 @@ int ath9k_init_debug(struct ath_hw *ah)
> > 
> >         debugfs_create_u16("airtime_flags", S_IRUSR | S_IWUSR,
> >         
> >                            sc->debug.debugfs_phy, &sc->airtime_flags);
> > 
> > +       debugfs_create_file("nf_override", S_IRUSR | S_IWUSR,
> > +                           sc->debug.debugfs_phy, sc, &fops_nf_override);
> > +
> 
> Why not simply:
>         debugfs_create_u32("nf_override", S_IRUSR|S_IWUSR ,
> sc->debug.debugfs_phy,
>                           &ah->nf_override);
> 
> One line patch :)

Thanks Janusz, good idea! That doesn't check the limits, which is probably not 
a big deal anyway. What bothers me more is that it doesn't update the noise 
floor immediately (ath9k_hw_loadnf()), which would be nice to have. Otherwise 
you have to wait up to ~30 seconds or so until the noise floor is updated next 
time. So I'd keep my variant for now, unless you have a good idea to fix the 
latter. :)

Cheers,
      Simon
Janusz.Dziedzic@tieto.com March 17, 2017, 12:44 p.m. UTC | #3
On 17 March 2017 at 09:55, Simon Wunderlich <sw@simonwunderlich.de> wrote:
> On Friday, March 17, 2017 9:48:07 AM CET Janusz Dziedzic wrote:
>> On 16 March 2017 at 16:13, Simon Wunderlich <sw@simonwunderlich.de> wrote:
>> > Introduce a debugfs option to manually override the noise floor,
>> > ignoring the automatically tuned noise floor of the driver/hw.
>> >
>> > In my tests with a AR9580 based module and a tx99 5 MHz interferer,
>> > I could tune the noisefloor to -95 dBm or above to allow communication
>> > again. The automatic noise floor calibration sometimes could adapt to
>> > the situation as well, but not reliably and permanently.
>> >
>> > I would consider this "feature" experimental and interesting for people
>> > debugging the noise floor calibration or other effects of the hardware.
>> >
>> > Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
>> > Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fit.fraunhofer.de>
>> > ---
>> >
>> >  drivers/net/wireless/ath/ath9k/calib.c |  5 ++-
>> >  drivers/net/wireless/ath/ath9k/debug.c | 62
>> >  ++++++++++++++++++++++++++++++++++ drivers/net/wireless/ath/ath9k/hw.h
>> >   |  1 +
>> >  3 files changed, 67 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/net/wireless/ath/ath9k/calib.c
>> > b/drivers/net/wireless/ath/ath9k/calib.c index 0f71146b781d..13ab6bc46775
>> > 100644
>> > --- a/drivers/net/wireless/ath/ath9k/calib.c
>> > +++ b/drivers/net/wireless/ath/ath9k/calib.c
>> > @@ -254,7 +254,9 @@ int ath9k_hw_loadnf(struct ath_hw *ah, struct
>> > ath9k_channel *chan)>
>> >                         if ((i >= AR5416_MAX_CHAINS) &&
>> >                         !IS_CHAN_HT40(chan))
>> >
>> >                                 continue;
>> >
>> > -                       if (h)
>> > +                       if (ah->nf_override)
>> > +                               nfval = ah->nf_override;
>> > +                       else if (h)
>> >
>> >                                 nfval = h[i].privNF;
>> >
>> >                         else
>> >
>> >                                 nfval = default_nf;
>> >
>> > @@ -348,6 +350,7 @@ int ath9k_hw_loadnf(struct ath_hw *ah, struct
>> > ath9k_channel *chan)>
>> >         return 0;
>> >
>> >  }
>> >
>> > +EXPORT_SYMBOL(ath9k_hw_loadnf);
>> >
>> >  static void ath9k_hw_nf_sanitize(struct ath_hw *ah, s16 *nf)
>> >
>> > diff --git a/drivers/net/wireless/ath/ath9k/debug.c
>> > b/drivers/net/wireless/ath/ath9k/debug.c index 43930c336987..2e64977a8ab6
>> > 100644
>> > --- a/drivers/net/wireless/ath/ath9k/debug.c
>> > +++ b/drivers/net/wireless/ath/ath9k/debug.c
>> > @@ -1191,6 +1191,65 @@ static const struct file_operations fops_tpc = {
>> >
>> >         .llseek = default_llseek,
>> >
>> >  };
>> >
>> > +static ssize_t read_file_nf_override(struct file *file,
>> > +                                    char __user *user_buf,
>> > +                                    size_t count, loff_t *ppos)
>> > +{
>> > +       struct ath_softc *sc = file->private_data;
>> > +       struct ath_hw *ah = sc->sc_ah;
>> > +       char buf[32];
>> > +       unsigned int len;
>> > +
>> > +       if (ah->nf_override == 0)
>> > +               len = sprintf(buf, "off\n");
>> > +       else
>> > +               len = sprintf(buf, "%d\n", ah->nf_override);
>> > +
>> > +       return simple_read_from_buffer(user_buf, count, ppos, buf, len);
>> > +}
>> > +
>> > +static ssize_t write_file_nf_override(struct file *file,
>> > +                                     const char __user *user_buf,
>> > +                                     size_t count, loff_t *ppos)
>> > +{
>> > +       struct ath_softc *sc = file->private_data;
>> > +       struct ath_hw *ah = sc->sc_ah;
>> > +       long val;
>> > +       char buf[32];
>> > +       ssize_t len;
>> > +
>> > +       len = min(count, sizeof(buf) - 1);
>> > +       if (copy_from_user(buf, user_buf, len))
>> > +               return -EFAULT;
>> > +
>> > +       buf[len] = '\0';
>> > +       if (strncmp("off", buf, 3) == 0)
>> > +               val = 0;
>> > +       else if (kstrtol(buf, 0, &val))
>> > +               return -EINVAL;
>> > +
>> > +       if (val > 0)
>> > +               return -EINVAL;
>> > +
>> > +       if (val < -120)
>> > +               return -EINVAL;
>> > +
>> > +       ah->nf_override = val;
>> > +
>> > +       if (ah->curchan)
>> > +               ath9k_hw_loadnf(ah, ah->curchan);
>> > +
>> > +       return count;
>> > +}
>> > +
>> > +static const struct file_operations fops_nf_override = {
>> > +       .read = read_file_nf_override,
>> > +       .write = write_file_nf_override,
>> > +       .open = simple_open,
>> > +       .owner = THIS_MODULE,
>> > +       .llseek = default_llseek,
>> > +};
>> > +
>> >
>> >  /* Ethtool support for get-stats */
>> >
>> >  #define AMKSTR(nm) #nm "_BE", #nm "_BK", #nm "_VI", #nm "_VO"
>> >
>> > @@ -1402,5 +1461,8 @@ int ath9k_init_debug(struct ath_hw *ah)
>> >
>> >         debugfs_create_u16("airtime_flags", S_IRUSR | S_IWUSR,
>> >
>> >                            sc->debug.debugfs_phy, &sc->airtime_flags);
>> >
>> > +       debugfs_create_file("nf_override", S_IRUSR | S_IWUSR,
>> > +                           sc->debug.debugfs_phy, sc, &fops_nf_override);
>> > +
>>
>> Why not simply:
>>         debugfs_create_u32("nf_override", S_IRUSR|S_IWUSR ,
>> sc->debug.debugfs_phy,
>>                           &ah->nf_override);
>>
>> One line patch :)
>
> Thanks Janusz, good idea! That doesn't check the limits, which is probably not
> a big deal anyway. What bothers me more is that it doesn't update the noise
> floor immediately (ath9k_hw_loadnf()), which would be nice to have. Otherwise
> you have to wait up to ~30 seconds or so until the noise floor is updated next
> time. So I'd keep my variant for now, unless you have a good idea to fix the
> latter. :)
>
I see, seems I miss ath9k_hw_loadnf() call :)

> Cheers,
>       Simon
diff mbox

Patch

diff --git a/drivers/net/wireless/ath/ath9k/calib.c b/drivers/net/wireless/ath/ath9k/calib.c
index 0f71146b781d..13ab6bc46775 100644
--- a/drivers/net/wireless/ath/ath9k/calib.c
+++ b/drivers/net/wireless/ath/ath9k/calib.c
@@ -254,7 +254,9 @@  int ath9k_hw_loadnf(struct ath_hw *ah, struct ath9k_channel *chan)
 			if ((i >= AR5416_MAX_CHAINS) && !IS_CHAN_HT40(chan))
 				continue;
 
-			if (h)
+			if (ah->nf_override)
+				nfval = ah->nf_override;
+			else if (h)
 				nfval = h[i].privNF;
 			else
 				nfval = default_nf;
@@ -348,6 +350,7 @@  int ath9k_hw_loadnf(struct ath_hw *ah, struct ath9k_channel *chan)
 
 	return 0;
 }
+EXPORT_SYMBOL(ath9k_hw_loadnf);
 
 
 static void ath9k_hw_nf_sanitize(struct ath_hw *ah, s16 *nf)
diff --git a/drivers/net/wireless/ath/ath9k/debug.c b/drivers/net/wireless/ath/ath9k/debug.c
index 43930c336987..2e64977a8ab6 100644
--- a/drivers/net/wireless/ath/ath9k/debug.c
+++ b/drivers/net/wireless/ath/ath9k/debug.c
@@ -1191,6 +1191,65 @@  static const struct file_operations fops_tpc = {
 	.llseek = default_llseek,
 };
 
+static ssize_t read_file_nf_override(struct file *file,
+				     char __user *user_buf,
+				     size_t count, loff_t *ppos)
+{
+	struct ath_softc *sc = file->private_data;
+	struct ath_hw *ah = sc->sc_ah;
+	char buf[32];
+	unsigned int len;
+
+	if (ah->nf_override == 0)
+		len = sprintf(buf, "off\n");
+	else
+		len = sprintf(buf, "%d\n", ah->nf_override);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static ssize_t write_file_nf_override(struct file *file,
+				      const char __user *user_buf,
+				      size_t count, loff_t *ppos)
+{
+	struct ath_softc *sc = file->private_data;
+	struct ath_hw *ah = sc->sc_ah;
+	long val;
+	char buf[32];
+	ssize_t len;
+
+	len = min(count, sizeof(buf) - 1);
+	if (copy_from_user(buf, user_buf, len))
+		return -EFAULT;
+
+	buf[len] = '\0';
+	if (strncmp("off", buf, 3) == 0)
+		val = 0;
+	else if (kstrtol(buf, 0, &val))
+		return -EINVAL;
+
+	if (val > 0)
+		return -EINVAL;
+
+	if (val < -120)
+		return -EINVAL;
+
+	ah->nf_override = val;
+
+	if (ah->curchan)
+		ath9k_hw_loadnf(ah, ah->curchan);
+
+	return count;
+}
+
+static const struct file_operations fops_nf_override = {
+	.read = read_file_nf_override,
+	.write = write_file_nf_override,
+	.open = simple_open,
+	.owner = THIS_MODULE,
+	.llseek = default_llseek,
+};
+
 /* Ethtool support for get-stats */
 
 #define AMKSTR(nm) #nm "_BE", #nm "_BK", #nm "_VI", #nm "_VO"
@@ -1402,5 +1461,8 @@  int ath9k_init_debug(struct ath_hw *ah)
 	debugfs_create_u16("airtime_flags", S_IRUSR | S_IWUSR,
 			   sc->debug.debugfs_phy, &sc->airtime_flags);
 
+	debugfs_create_file("nf_override", S_IRUSR | S_IWUSR,
+			    sc->debug.debugfs_phy, sc, &fops_nf_override);
+
 	return 0;
 }
diff --git a/drivers/net/wireless/ath/ath9k/hw.h b/drivers/net/wireless/ath/ath9k/hw.h
index 496e3cd1b509..eba478f052b9 100644
--- a/drivers/net/wireless/ath/ath9k/hw.h
+++ b/drivers/net/wireless/ath/ath9k/hw.h
@@ -803,6 +803,7 @@  struct ath_hw {
 	u32 rfkill_gpio;
 	u32 rfkill_polarity;
 	u32 ah_flags;
+	s16 nf_override;
 
 	bool reset_power_on;
 	bool htc_reset_init;