Scan request looks ignored when wpa_state is in scanning state with dbus interface

[Naveen Singh]

I see a similar problem with ath6k where schedule scan never completes
and then subsequent scan always return IN_PROGRESS. Since our product
does not require schedule scan, I ended up disabling schedule scan in
driver.

Regards
Naveen

On Mon, Feb 29, 2016 at 2:27 PM, Ben Greear <greearb at candelatech.com> wrote:
> On 02/29/2016 02:20 PM, Johannes Berg wrote:
>>
>> On Thu, 2016-02-25 at 10:36 -0800, Ben Greear wrote:
>
>
>>> At least with ath10k, I've seen cases where scan-complete is never
>>> sent
>>> back to supplicant.  I added a timeout at that time that dealt with
>>> the issue,
>>> not sure it would fix this problem or not.
>>>
>>> https://github.com/greearb/hostap-ct/commit/913f01e9d0384ed5e99b396f0
>>> 50233d9204dd041
>>>
>>
>> That won't actually help you much, unless somehow the event got lost
>> between cfg80211 and wpa_s; if it never arrived you'll never be allowed
>> to scan again and really need to fix ath10k instead.
>>
>> There's a very slight chance of us failing to allocate memory when
>> sending the event; we could attempt to fix that by preallocating? But
>> it cannot actually happen since small GFP_KERNEL apparently can't
>> actually fail.
>
>
> It's been a year or two, but I think the issue was that firmware crashed
> during scan, and the ath10k driver didn't do some sort of cleanup properly.
>
> Note that supplicant RX buffers for netlink socket in supplicant could also
> overflow
> and cause pkt loss there, but I don't know if that was what was
> happening in my case.
>
> Either way, I haven't had this problem any time recently, so either
> the firmware/driver/stack is fixed (I don't see any firmware scan
> crashes anymore, for instance), or my work-around in supplicant
> is sufficient.
>
> Thanks,
> Ben
>
>
> --
> Ben Greear <greearb at candelatech.com>
> Candela Technologies Inc  http://www.candelatech.com
>
>
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