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Date: Mon, 15 Oct 2012 09:17:50 +0530
From: Mahesh Palivela <maheshp@posedge.com>
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To: Johannes Berg <johannes@sipsolutions.net>
CC: "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
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	"Luis R. Rodriguez" <mcgrof@do-not-panic.com>
Subject: Re: [RFC v2] cfg80211: VHT regulatory
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On 10/10/2012 02:41 PM, Johannes Berg wrote:
>>
>> we need "channel starting frequency" anyways for calculating center
>> freq. so we can use same constant for computing primary chan freq as
>> well. why switch to prim_chan_offset?
>
> I think it'd be easier for drivers, since they typically seem to use
> that to specify the control channel. If we give the frequency, they'll
> have to calculate back to offset. The offset is also used in IEs etc.,
> so I think overall that would simplify things.

Offset means we specify one of -70, -50, -30, -10, +10, +30, +50, +70 
for 80/160 MHz BW from center freq.
For ex. 80 MHz BW of channel 36, 40, 44 and 48 center freq is 42. If 
control chan 36, then we specify offset -30. Is that what we want?

VHT IEs doesn't use offset anywhere. I am not sure why/where drivers use 
offset values.