Re: QCA9984 VHT160 support

From: Michal Kazior <michal.kazior@tieto.com>
To: Sebastian Gottschall <s.gottschall@dd-wrt.com>,
	"ath10k@lists.infradead.org" <ath10k@lists.infradead.org>
Subject: Re: QCA9984 VHT160 support
Date: Tue, 17 May 2016 14:18:17 +0200	[thread overview]
Message-ID: <CA+BoTQnopmxAQaWCyNvy20uWB65F=pMcoQ9Pz4LNWo3VGBMpHg@mail.gmail.com> (raw)
In-Reply-To: <4e407b2c-29f9-3c74-ea94-4206632441c3@dd-wrt.com>

+ re-adding ath10k list

On 17 May 2016 at 14:05, Sebastian Gottschall <s.gottschall@dd-wrt.com> wrote:
>Am 17.05.2016 um 14:00 schrieb Michal Kazior:
>> On 17 May 2016 at 13:43, Sebastian Gottschall <s.gottschall@dd-wrt.com> wrote:
>>> Attached you will find a testing patch for VHT160 support. i tested it today
>>> on a QCA9984 device and it seems to work.
>>> feel free to make any corrections
>> Hi,
>>
>> Send patches inline, please. Preferably via git send-email. It's a lot
>> easier to review them this way.
> unfortunaty i dont work with git right now and i wanted to send it to
> the list first for getting comments.
> since the patch is also very small, it should be that complicated
>>
>>  From a quick glance vht capabilities setup looks weird:
>>
>>> if (ar->vht_cap_info &  IEEE80211_VHT_CAP_SHORT_GI_160) {
>>>    vht_cap.cap |= IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ;
>>>    vht_cap.cap |= IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ;
>>> }
>> Why? Is this really necessary?
> the firmware does not report correct flags. just SHORT_GI_160.
> i reviewed the firmware sourcecodes and found out that this is maybe a
> misstake of the QCA developers.
> so we need to add the 160MHZ support flags locally using the
> SHORT_GI_160 which is always set on QCA9984.
> otherwise mac80211 will not be capable of running vht160.

I'm not sure if SGI160 implies 80+80.

>> I would expect IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ and
>> IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ to be already set in
>> ar->vht_cap_info if the chip supports 160 or 80+80.
>me too. but it isnt :-)

Sigh. A comment explaining that would be really nice.

>> You also don't seem to handle 80+80 because you just as phymode to 160
>> regardless of center frequencies:
>>
>>> !ath10k_peer_assoc_h_vht_masked(vht_mcs_mask)) {
>>>     if (sta->bandwidth == IEEE80211_STA_RX_BW_80)
>>>       phymode = MODE_11AC_VHT80;
>>>     else if (sta->bandwidth == IEEE80211_STA_RX_BW_160)
>>>       phymode = MODE_11AC_VHT160;
>>>     else if (sta->bandwidth == IEEE80211_STA_RX_BW_40)
>>>       phymode = MODE_11AC_VHT40;
>>>     else if (sta->bandwidth == IEEE80211_STA_RX_BW_20)
> there is no 80+80 STA_RX_BW flag. i dont know how to handle this. and
> yes, just 160 mhz is tested right now. right now it looks like mac80211
> is not 80+80 ready.

Hmm.. I wouldn't advertise 80+80 support then. All the more since
there's no way of telling whether hw/fw actually supports it in the
first place.

Michal

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