Subject: Re: [PATCH] cfg80211/nl80211: add DFS offload flag
To: Dmitrii Lebed <dlebed@quantenna.com>,
        Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>,
        linux-wireless@vger.kernel.org
References: <20180221105635.5824-1-sergey.matyukevich.os@quantenna.com>
 <5A8D521C.2030502@broadcom.com>
 <0e3d5af0-bc6b-d98f-02f2-cc4d585e6cd1@quantenna.com>
Cc: Johannes Berg <johannes@sipsolutions.net>,
        Igor Mitsyanko <igor.mitsyanko.os@quantenna.com>,
        Avinash Patil <avinashp@quantenna.com>
From: Arend van Spriel <arend.vanspriel@broadcom.com>
Message-ID: <5A8DCF9E.90505@broadcom.com> (sfid-20180221_205932_219960_C69BF713)
Date: Wed, 21 Feb 2018 20:59:26 +0100
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Sender: linux-wireless-owner@vger.kernel.org

On 2/21/2018 12:25 PM, Dmitrii Lebed wrote:
>
> On 21.02.2018 14:03, Arend van Spriel wrote:
>> On 2/21/2018 11:56 AM, Sergey Matyukevich wrote:
>>> From: Dmitry Lebed <dlebed@quantenna.com>
>>>
>>> Add wiphy flag to indicate that HW does all DFS actions by itself.
>>> User-space functionality already implemented in hostapd using
>>> vendor-specific (QCA) OUI to advertise HW support.
>>> Need to introduce generic flag to inform about DFS offload support.
>>> For deivces with DFS_OFFLOAD flag set user-space will no longer
>>> need to issue CAC or do any actions in response to
>>> "radar detected" events. HW will do everything by itself and send
>>> events to user-space to idicate that CAC was started/finished, etc.
>>>
>>> Signed-off-by: Dmitrii Lebed <dlebed@quantenna.com>
>>> ---
>>>   include/net/cfg80211.h       | 7 ++++++-
>>>   include/uapi/linux/nl80211.h | 9 +++++++++
>>>   net/wireless/nl80211.c       | 7 +++++++
>>>   3 files changed, 22 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
>>> index ed3a28105d6c..b2d17993ae4d 100644
>>> --- a/include/net/cfg80211.h
>>> +++ b/include/net/cfg80211.h
>>> @@ -3241,6 +3241,11 @@ struct cfg80211_ops {
>>>    * @WIPHY_FLAG_IBSS_RSN: The device supports IBSS RSN.
>>>    * @WIPHY_FLAG_MESH_AUTH: The device supports mesh authentication
>>> by routing
>>>    *  auth frames to userspace. See @NL80211_MESH_SETUP_USERSPACE_AUTH.
>>> + * @WIPHY_FLAG_DFS_OFFLOAD: Device will do all DFS-related actions
>>> by itself,
>>> + *   informing user-space about CAC progress, radar detection event,
>>> + *   channel change triggered by radar detection event.
>>> + *   No need to start CAC from user-space, no need to react to
>>> + *   "radar detected" event.
>>
>> wiphy flags are kinda deprecated. At least no new flags should be added.
>> Instead use EXT_FEATURE flag.
>>
>> Regards,
>> Arend
> Thanks for clarification, Arend. I'll change it to use new EXT_FEATURE
> flag.
> BTW, are there any concerns regarding adding generic DFS_OFFLOAD driver
> capability?
> I want to add DFS_OFFLOAD support to qtnfmac driver and fix hostapd to
> support
> generic EXT_FEATURE flag as well as vendor-specific capabilities.

I suppose you are referring to the qcom vendor-specific stuff for DFS 
offload. I can not speak for Kalle nor Johannes, but you have my thumbs 
up. I am not familiar enough with the qcom implementation to say whether 
there are concerns.

> Thanks,
> Dmitrii
>>
>>>    * @WIPHY_FLAG_SUPPORTS_FW_ROAM: The device supports roaming
>>> feature in the
>>>    *  firmware.
>>>    * @WIPHY_FLAG_AP_UAPSD: The device supports uapsd on AP.
>>
>
>
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Regards,
Arend