[ath9k-devel] Disabling the third antenna for AR9380 in ath9k

Commit Message

Mohammed Shafi June 23, 2011, 12:42 p.m. UTC

On Thu, Jun 23, 2011 at 5:52 PM, Adrian Chadd <[e-mail]> wrote:
> As I said, there's a value in the ath9k code that gets set based on
> the chipset type.
>
> static void setup_ht_cap(struct ath_softc *sc,
>                         struct ieee80211_sta_ht_cap *ht_info)
>
> in init.c
>
> That should be all you need to do to communicate to the higher layers
> that you only support 2 streams.

Adrian thanks a lot for the pointer, should this be sufficient? or are
we still missing communicating something to the upper layer, all i can
see is this affects rx_mask sent to the upper layer



>
> You're checking the wrong place. You're seeing _TX_ errors, but what
> you're not seeing (likely because you don't have a 3 stream peer) is
> that you're still advertising supporting MCS0->24, so peers may send
> you MCS16->24 even though you can't receive it.
>
> The correct way is to patch the driver to only enable 2 streams in the
> HT capability setup, so mac80211 and the rate control code only
> advertises MCS0-15 and TX'es MCS0-15 respectively.
>
> (You have to do this as well as disabling the third chain btw.)
>
>
>
> Adrian
>
> On 23 June 2011 20:16, Mohammed Shafi <[e-mail]> wrote:
>> On Thu, Jun 23, 2011 at 5:26 PM, Fred Matthews <[e-mail]> wrote:
>>>
>>>
>>> Hi,
>>>
>>> Regarding streams used in Minstrel RC, I found that in "net/mac80211/rc80211_minstrel_ht.h", at line 16, there is "#define MINSTREL_MAX_STREAMS  3", that sets the number of streams for minstrel RC.
>>>
>>> Now can someone help to pass this onto debugfs, so that we can change from 3 streams to 2 streams at runtime like the rx_chainmask. I tried creating a u8 stream_number and struct dentry *dbg_stream_number in the header file, then a debugfs_create_u8 in the c file. Then used it to redefine MINSTREL_MAX_STREAMS, but when I tested this I got errors, therefore, can anyone kindly share a patch to do this correctly.
>>
>> hi,
>>
>> i am not familiar with the minstrel rate control, but as you had asked
>> I grep'd for MINSTREL_MAX_STREAMS to see if we can quickly add a debug
>> entry to change it. but usage like this below suggests we can quickly
>> hack the macro to 2 rather than adding a debug entry
>>
>> const struct mcs_group minstrel_mcs_groups[] = {
>>        MCS_GROUP(1, 0, 0),
>>        MCS_GROUP(2, 0, 0),
>> #if MINSTREL_MAX_STREAMS >= 3
>>        MCS_GROUP(3, 0, 0),
>> #endif
>>
>>
>>>
>>> Thanks in advance
>>>
>>>
>>>
>>> On Wed, Jun 22, 2011 at 3:57 PM, Mohammed Shafi wrote:
>>>> On Wed, Jun 22, 2011 at 6:12 PM, Fred Matthews wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> I used that command to disable the third antenna, and applied it to both AP
>>>>> and STA AR9380 NICs.
>>>>> I then performed an IPerf test between both and then captured the statistics
>>>>> from the sender, (below) .
>>>>> You can see that in rc_stats (minstrel), the rate control actually
>>>>> "attempts" sending on 3 stream MCSs (16-23) around 256 times each.
>>>>
>>>> just a guess. as we are changing the chain mask via debugfs and there
>>>> may be a chance we may not have informed the minstrel rate control
>>>> which is maintained in upper layer(mac80211) and it might be taking
>>>> what we have configured the chain masks while we had initialized the
>>>> device and i have very little idea about ministrel rate control
>>>>
>>>>>
>>>>> Is there any way to prevent the RC from even attempting those rates, as if I
>>>>> where to fully imitate an AR9280, it shouldnt attempt at those MCSs.
>>>>
>>>> may be we can try with ath9k rate control, and see what happens which
>>>> is within the ath9k driver and affects xmit.c and it may have been
>>>> informed of the chain mask change.
>>>>
>>>>>
>>>>> Can Susinders comments also be detailed.
>>>>>
>>>>> Thanks in advance
>>>>>
>>>>> # cat /sys/kernel/debug/ieee80211/phy0/netdev\:wlan0/stations/00\MAC/
>>>>>
>>>>> AUTH
>>>>> ASSOC
>>>>> AUTHORIZED
>>>>> WME
>>>>> ht supported
>>>>> cap: 0x11ce
>>>>>     HT20/HT40
>>>>>     SM Power Save disabled
>>>>>     RX HT40 SGI
>>>>>     TX STBC
>>>>>     RX STBC 1-stream
>>>>>     Max AMSDU length: 7935 bytes
>>>>>     DSSS/CCK HT40
>>>>> ampdu factor/density: 3/6
>>>>> MCS mask: ff ff ff 00 00 00 00 00 00 00
>>>>> MCS tx params: 1
>>>>> 792
>>>>> 150 ffff ffff ffff ffff ffff 60 ffff ffff ffff ffff ffff ffff ffff ffff ffff
>>>>> a40
>>>>> -77
>>>>> 0
>>>>> type      rate     throughput  ewma prob   this prob  this succ/attempt
>>>>> success    attempts
>>>>> HT20/LGI    MCS0        6.6       99.9      100.0          0(  0)        163
>>>>>         230
>>>>> HT20/LGI    MCS1       13.1      100.0      100.0          0(  0)         75
>>>>>          75
>>>>> HT20/LGI    MCS2       19.3      100.0      100.0          0(  0)        252
>>>>>         252
>>>>> HT20/LGI    MCS3       25.4      100.0      100.0          0(  0)         75
>>>>>          75
>>>>> HT20/LGI    MCS4       36.2       97.5      100.0          0(  0)        413
>>>>>         474
>>>>> HT20/LGI    MCS5        0.0        0.0        0.0          0(  0)          0
>>>>>          76
>>>>> HT20/LGI    MCS6        0.0        0.0        0.0          0(  0)          0
>>>>>          80
>>>>> HT20/LGI    MCS7        0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT20/LGI    MCS8       13.1      100.0      100.0          0(  0)         75
>>>>>          75
>>>>> HT20/LGI    MCS9       25.4      100.0      100.0          0(  0)         70
>>>>>          70
>>>>> HT20/LGI    MCS10      34.2       92.2      100.0          0(  0)         79
>>>>>          82
>>>>> HT20/LGI    MCS11       0.0        0.0        0.0          0(  0)          0
>>>>>          76
>>>>> HT20/LGI    MCS12       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT20/LGI    MCS13       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT20/LGI    MCS14       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT20/LGI    MCS15       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT20/LGI    MCS16       0.0        0.0        0.0          0(  0)          0
>>>>>          75
>>>>> HT20/LGI    MCS17       0.0        0.0        0.0          0(  0)          0
>>>>>          68
>>>>> HT20/LGI    MCS18       0.0        0.0        0.0          0(  0)          0
>>>>>          85
>>>>> HT20/LGI    MCS19       0.0        0.0        0.0          0(  0)          0
>>>>>         257
>>>>> HT20/LGI    MCS20       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT20/LGI    MCS21       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT20/LGI    MCS22       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT20/LGI    MCS23       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/LGI    MCS0       13.6      100.0      100.0          0(  0)         75
>>>>>          75
>>>>> HT40/LGI    MCS1       26.5      100.0      100.0          0(  0)         72
>>>>>          72
>>>>> HT40/LGI    MCS2       38.3      100.0      100.0          0(  0)         73
>>>>>          73
>>>>> HT40/LGI    MCS3       49.7       99.9      100.0          0(  0)         70
>>>>>          73
>>>>> HT40/LGI    MCS4        0.0        0.0        0.0          0(  0)         10
>>>>>        1220
>>>>> HT40/LGI    MCS5        0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/LGI    MCS6        0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/LGI    MCS7        0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/LGI    MCS8       26.2       98.9      100.0          0(  0)         73
>>>>>          74
>>>>> HT40/LGI    MCS9       49.3       99.2      100.0          0(  0)         67
>>>>>          69
>>>>> HT40/LGI    MCS10      20.5       28.9        0.0          0(  0)         14
>>>>>         255
>>>>> HT40/LGI    MCS11       0.0        0.0        0.0          0(  0)          0
>>>>>         257
>>>>> HT40/LGI    MCS12       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/LGI    MCS13       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/LGI    MCS14       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/LGI    MCS15       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/LGI    MCS16       0.0        0.0        0.0          0(  0)          0
>>>>>          74
>>>>> HT40/LGI    MCS17       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/LGI    MCS18       0.0        0.0        0.0          0(  0)          0
>>>>>         255
>>>>> HT40/LGI    MCS19       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/LGI    MCS20       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/LGI    MCS21       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/LGI    MCS22       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/LGI    MCS23       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/SGI    MCS0       15.1      100.0      100.0          0(  0)         70
>>>>>          70
>>>>> HT40/SGI    MCS1       29.2      100.0      100.0          0(  0)         72
>>>>>          72
>>>>> HT40/SGI  t MCS2       38.5       91.3      100.0          0(  0)         81
>>>>>          83
>>>>> HT40/SGI   PMCS3       54.3       99.5      100.0          0(  0)      66536
>>>>>       67803
>>>>> HT40/SGI    MCS4        0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/SGI    MCS5        0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/SGI    MCS6        0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/SGI    MCS7        0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/SGI    MCS8       29.2      100.0      100.0          0(  0)         67
>>>>>          67
>>>>> HT40/SGI T  MCS9       54.6       99.9      100.0          0(  0)     310227
>>>>>      312339
>>>>> HT40/SGI    MCS10      22.7       29.3      100.0          0(  0)         14
>>>>>     46.8 Mbits/sec    255
>>>>> HT40/SGI    MCS11       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/SGI    MCS12       0.0        0.0        0.0          0(  0)          0
>>>>>         255
>>>>> HT40/SGI    MCS13       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/SGI    MCS14       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/SGI    MCS15       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/SGI    MCS16       0.0        0.0        0.0          0(  0)          0
>>>>>          68
>>>>> HT40/SGI    MCS17       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/SGI    MCS18       0.0        0.0        0.0          0(  0)          0
>>>>>         255
>>>>> HT40/SGI    MCS19       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/SGI    MCS20       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/SGI    MCS21       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/SGI    MCS22       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>> HT40/SGI    MCS23       0.0        0.0        0.0          0(  0)          0
>>>>>         256
>>>>>
>>>>> Total packet count::    ideal 365056      lookaround 13702
>>>>> Average A-MPDU length: 5.4
>>>>>
>>>>>> Date: Tue, 21 Jun 2011 14:25:36 +0530
>>>>>> Subject: Re: [ath9k-devel] Disabling the third antenna for AR9380 in ath9k
>>>>>> From: [e-mail]
>>>>>> To: [e-mail]
>>>>>> CC: [e-mail]; [e-mail];
>>>>>> [e-mail]; [e-mail];
>>>>>> [e-mail]
>>>>>>
>>>>>> On Tue, Jun 21, 2011 at 2:07 AM, Fred Matthews
>>>>>> wrote:
>>>>>> > Hi all,
>>>>>> > I am installing the AR9380 NIC on laptops, but some only have two UFL
>>>>>> > connectors, and thus I was wondering if using only two of the UFL
>>>>>> > antenna
>>>>>> > ports will have any negative effect or difference than installing a 2x2
>>>>>> > NIC
>>>>>> > (AR9280 for example which has only 2 ports anyway). Please kindly
>>>>>> > explain
>>>>>> > with references if possible.
>>>>>> > Also for example is there anyway to disable transmission on the third
>>>>>> > UFL
>>>>>> > port (antenna) from ath9k or otherwise.
>>>>>> > Thank you all very much
>>>>>>
>>>>>> you can change the tx/rx chainmask for 3x3 AR9380 to disable
>>>>>> transmission on the third antenna
>>>>>> cd /sys/kernel/debug/ieee80211/phy0/ath9k# echo 0x3 > tx_chainmask
>>>>>> cd /sys/kernel/debug/ieee80211/phy0/ath9k# echo 0x3 > rx_chainmask
>>>>>>
>>>>>> after this, ideally it should operate as 2x2 device as per Susinders
>>>>>> comments. but if you got AR9280 please try to use that if 2 antenna is
>>>>>> the constraint.
>>>>>>
>>>>>>
>>>>>> > _______________________________________________
>>>>>> > ath9k-devel mailing list
>>>>>> > [e-mail]
>>>>>> > https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>>>>>> >
>>>>>> >
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>                                          --
>>> To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
>>> the body of a message to [e-mail]
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>
>>
>>
>>
>> --
>> shafi
>>
>

Patch

diff --git a/drivers/net/wireless/ath/ath9k/init.c
b/drivers/net/wireless/ath/ath9k/init.c
index 50103b2..079359e 100644
--- a/drivers/net/wireless/ath/ath9k/init.c
+++ b/drivers/net/wireless/ath/ath9k/init.c
@@ -251,6 +251,10 @@  static void setup_ht_cap(struct ath_softc *sc,
                max_streams = 3;
        else
                max_streams = 2;
+       /*
+        * hard code max_streams
+        */
+               max_streams = 2;

        if (AR_SREV_9280_20_OR_LATER(ah)) {
                if (max_streams >= 2)