compat-wireless-2014-05-22 breaks ath10k in an Archer C7 v2

[Andy Lutomirski]

On Thu, Jun 5, 2014 at 3:26 AM, Kalle Valo <kvalo at qca.qualcomm.com> wrote:
> Andy Lutomirski <luto at amacapital.net> writes:
>
>> On Thu, May 29, 2014 at 12:48 AM, Michal Kazior <michal.kazior at tieto.com> wrote:
>>> +ath10k at lists.infradead.org
>>>
>>> On 28 May 2014 20:35, Andy Lutomirski <luto at amacapital.net> wrote:
>>>> It dies with 'otp calibration failed: 2'.
>>>>
>>>> Some older version of the driver seemed to work fine.
>>>
>>> ath10k did not verify otp result before so it could load successfully
>>> despite errors.
>>>
>>> Someone raised this problem yesterday on IRC. I'm not really sure how
>>> we should deal with this properly.
>>
>> Ideally, someone from Atheros could figure out what the error is.
>
> Michal already did. The error means that for some reason the
> calibaration data was not found from OTP. OTP is the storage area where
> the calibration data is normally stored within QCA9880.

Ah -- I misunderstood.  I assumed that the OTP read was failing
mysteriously and that expert input was needed to resolve that mystery
:)

>
>> Barring that, the card seems to work okay without otp (I don't even
>> know what otp is), so just warning and continuing to load might be
>> better than bailing.
>
> This means that your card is not properly calibrated and it doesn't
> function in an optimal way (for example range or throughput is less than
> what it could be).
>
> Do you see that with all Archer C7 v2 devices or with just one? One
> possibility is that the calibration data is actually stored outside of
> QCA9880 board, for example in the host flash or similar. I don't have
> that AP, can someone else see where the calibration data is stored?

I only have one of these.  I put a likely looking directory of the GPL
sources here:

http://web.mit.edu/luto/www/archerc7_gpl/atheros/

I'm not entirely sure what I'm looking for, but this might be it:

http://web.mit.edu/luto/www/archerc7_gpl/atheros/otp.c

I don't really know what I'm looking for, though.

--Andy