Setting single rate in ath10k broken by "reject/clear user rate mask if not usable"

[Ben Greear]

On 11/13/2017 02:09 AM, Johannes Berg wrote:
> On Fri, 2017-10-27 at 13:41 -0700, Ben Greear wrote:
>
>> ath10k ignores the tx rateset pretty much entirely when sending management
>> frames, so even if you set the tx rateset to have only VHT MCS 8,
>> management frames are still sent with legacy ratesets.
>
> So that's a driver bug.

The firmware gives the ability to set a single fixed rate for
multicast, and another for management frames.  It is possibly to
set the tx-data frame rate to another fixed rate, or to a more
normal rateset.  But, you do not have full control over setting
tx-data rates (no way to tell stock firmware to use 6Mbps /g rate and
mcs 8 (only), for instance).  The multicast and mgt frame API is not hooked up in the
stock driver as far as I know.

But even if they were, I don't see a good way to make this fit
with the mac80211 txrate setting framework.

What is the suggested approach to propagate a rateset set with
'iw' to a firmware with these limitations?

For the Intel firmware NICs, how do they set management and bcast
tx rates?

>> My end goal about this part is to be able to configure a single tx rate
>> and have that be allowed again, at least with ath10k.
>>
>> Maybe a new flag for drivers like ath10k that at least somewhat ignore
>> the tx-rateset for management frames, and this flag would allow us to
>> bypass the cannot-set-single-rate check?
>
> What? No, I'm not going to put a driver bug into the API like that!

Thanks for the constructive feedback.

--Ben

>
> johannes
>


-- 
Ben Greear <greearb at candelatech.com>
Candela Technologies Inc  http://www.candelatech.com