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Date:   Mon, 24 Oct 2022 16:06:08 +0300
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Subject: Re: How to use the rate control in mac80211?
To:     Johannes Berg <johannes@sipsolutions.net>,
        "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
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 <472d5d4687ddbecfbf97419d223b4d1b472777e1.camel@sipsolutions.net>
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From:   Bitterblue Smith <rtl8821cerfe2@gmail.com>
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On 23/10/2022 18:53, Johannes Berg wrote:
> Hi,
> 
>> I thought it's like this:
>> 1) don't set HAS_RATE_CONTROL
> 
> yes
> 
>> 2) tell the chip to use the rate from tx_info->control.rates[0]
> 
> I'd prefer you didn't, that's also very limited :-)
> 
>> 3) report if the frame was acked or not
> 
> Kind of.
> 
> It'd be better if new drivers used sta_rate_tbl_update method, so it'd
> be something like
> 
>  1) don't set HAS_RATE_CONTROL
>  2) implement sta_rate_tbl_update(), using the table of rates given
>     there to instruct the device to transmit frames at those rates
>  3) on TX success/failure, fill in a struct ieee80211_rate_status array 
>     that indicates which rates were used and how many times until the
>     eventual success or failure; this is in struct ieee80211_tx_status
>  3) alternatively, fill in the tx_info rates array the same way and
>     report it that way, but that's less flexible
> 
> 
> johannes

I got it to work! But I had to use tx_info->control.rates[0] when 
IEEE80211_TX_CTL_RATE_CTRL_PROBE is set, otherwise the rate table only
contains MCS0.