[ath9k-devel] adjust the CCA (Clear Channel Assessment) value for ath9k

[Brandon Combs <brmcombs@iusb.edu>]

> > I also need to adjust the CCA (Clear Channel Assessment)value. Does anyone 
know
> > how to increase the CCA threshold so that one can get a node to send even 
when
> > it senses an unclear channel? Here is the code segments from
> > /source/drivers/net/wireless/ath/ath9k/ar9002_phy.h which I believe I need 
to
> > adjust to increase the CCA threshold but I am not quite sure how (thanks for 
any help, Note: I am using AR9280 chip set):
> >
> > 127 #define AR_PHY_CCA ? ? ? ? ? ? ? ? ?0x9864
> > 128 #define AR_PHY_MINCCA_PWR ? ? ? ? ? 0x0FF80000
> > 129 #define AR_PHY_MINCCA_PWR_S ? ? ? ? 19
> > 130 #define AR_PHY_CCA_THRESH62 ? ? ? ? 0x0007F000
> > 131 #define AR_PHY_CCA_THRESH62_S ? ? ? 12
> > 132 #define AR9280_PHY_MINCCA_PWR ? ? ? 0x1FF00000
> > 133 #define AR9280_PHY_MINCCA_PWR_S ? ? 20
> > 134 #define AR9280_PHY_CCA_THRESH62 ? ? 0x000FF000
> > 135 #define AR9280_PHY_CCA_THRESH62_S ? 12

> > 581 #define AR_PHY_CCA_NOM_VAL_5416_2GHZ ? ? ? ? ? ?-90
> > 582 #define AR_PHY_CCA_NOM_VAL_5416_5GHZ ? ? ? ? ? ?-100
> > 583 #define AR_PHY_CCA_MIN_GOOD_VAL_5416_2GHZ ? ? -100
> > 584 #define AR_PHY_CCA_MIN_GOOD_VAL_5416_5GHZ ? ? -110
> > 585 #define AR_PHY_CCA_MAX_GOOD_VAL_5416_2GHZ ? ? -80
> > 586 #define AR_PHY_CCA_MAX_GOOD_VAL_5416_5GHZ ? ? -90
> > 587
> > 588 #define AR_PHY_CCA_NOM_VAL_9280_2GHZ ? ? ? ? -112
> > 589 #define AR_PHY_CCA_NOM_VAL_9280_5GHZ ? ? ? ? -112
> > 590 #define AR_PHY_CCA_MIN_GOOD_VAL_9280_2GHZ ?-127
> > 591 #define AR_PHY_CCA_MIN_GOOD_VAL_9280_5GHZ ?-122
> > 592 #define AR_PHY_CCA_MAX_GOOD_VAL_9280_2GHZ ?-97
> > 593 #define AR_PHY_CCA_MAX_GOOD_VAL_9280_5GHZ ?-102
> > 594
> > 595 #define AR_PHY_CCA_NOM_VAL_9285_2GHZ ? ? ? ? ? -118
> > 596 #define AR_PHY_CCA_MIN_GOOD_VAL_9285_2GHZ ? ?-127
> > 597 #define AR_PHY_CCA_MAX_GOOD_VAL_9285_2GHZ ? ?-108
> > 598
> > 599 #define AR_PHY_CCA_NOM_VAL_9271_2GHZ ? ? ? ? ? ? -118
> > 600 #define AR_PHY_CCA_MIN_GOOD_VAL_9271_2GHZ ? ? ?-127
> > 601 #define AR_PHY_CCA_MAX_GOOD_VAL_9271_2GHZ ? ? ?-116
> > 602
> > 603 #define AR_PHY_CCA_NOM_VAL_9287_2GHZ ? ? ? ? ? -120
> > 604 #define AR_PHY_CCA_MIN_GOOD_VAL_9287_2GHZ ? ?-127
> > 605 #define AR_PHY_CCA_MAX_GOOD_VAL_9287_2GHZ ? ?-110
> >
> > Sagar Bijwe <sag.bijwe <at> gmail.com> writes:
> >>
> >> I wish to disable CCA for ath9k. Can anyone tell me how this can be 
achieved?
> > As far as I see it, modifying values of?AR9280_PHY_CCA_THRESH62
> > AR9280_PHY_CCA_THRESH62_S (present in phy.h)should do. -Sagar
> >>
> 
> unfortunately its not a feature that we can simply disable it and I
> guess it requires a deeper understanding of hardware code to do this.
/////////////////////////////////////////////////////////////////////

I realize that "it requires a deeper understanding of hardware code to" increase 
the CCA threshold. Is this maybe not the correct mailing list to ask this "deep" 
of a question?
Can someone please point me in the right direction on where to learn this 
information? I have throughly looked through linuxwireless.org documentation and 
I searched the web for hours and I cannot find any reference to adjusting CCA.

Is it not just simply a matter of changing one of the "#define AR_PHY_...." and 
recompiling the driver in order to increase the CCA threshold?  

I really, really appreciate ANY info on adjusting the AR9280 CCA threshold!