P2P support in brcmfmac

P2P support in brcmfmac

[Arend van Spriel]

Hi John,

In 3.9 we introduced P2P support in brcmfmac which was functional using
current wpa_supplicant P2P support, but we did not yet support the
P2P_DEVICE user-space API.

Last week I enabled that in brcmfmac testing it with wpa_supplicant
patches for P2P_DEVICE support from David Spinadel. So I do have a
couple of brcmfmac patches to make that work and would like to submit
those for 3.9 although it is not strictly a bug fix. Would you consider
taking these?

Regards,
Arend

Re: P2P support in brcmfmac

[John W. Linville]

On Wed, Mar 27, 2013 at 12:51:35PM +0100, Arend van Spriel wrote:

> In 3.9 we introduced P2P support in brcmfmac which was functional using
> current wpa_supplicant P2P support, but we did not yet support the
> P2P_DEVICE user-space API.
> 
> Last week I enabled that in brcmfmac testing it with wpa_supplicant
> patches for P2P_DEVICE support from David Spinadel. So I do have a
> couple of brcmfmac patches to make that work and would like to submit
> those for 3.9 although it is not strictly a bug fix. Would you consider
> taking these?

That doesn't sound to me like something that would be worthy of such
an exception.

John
-- 
John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.

Re: P2P support in brcmfmac

[Johannes Berg]

On Wed, 2013-03-27 at 08:22 -0400, John W. Linville wrote:
> On Wed, Mar 27, 2013 at 12:51:35PM +0100, Arend van Spriel wrote:
> 
> > In 3.9 we introduced P2P support in brcmfmac which was functional using
> > current wpa_supplicant P2P support, but we did not yet support the
> > P2P_DEVICE user-space API.
> > 
> > Last week I enabled that in brcmfmac testing it with wpa_supplicant
> > patches for P2P_DEVICE support from David Spinadel. So I do have a
> > couple of brcmfmac patches to make that work and would like to submit
> > those for 3.9 although it is not strictly a bug fix. Would you consider
> > taking these?
> 
> That doesn't sound to me like something that would be worthy of such
> an exception.

Maybe just make a small patch to disable the other API, so we don't end
up having to support both?

johannes

Re: P2P support in brcmfmac

[John W. Linville]

On Wed, Mar 27, 2013 at 01:34:58PM +0100, Johannes Berg wrote:
> On Wed, 2013-03-27 at 08:22 -0400, John W. Linville wrote:
> > On Wed, Mar 27, 2013 at 12:51:35PM +0100, Arend van Spriel wrote:
> > 
> > > In 3.9 we introduced P2P support in brcmfmac which was functional using
> > > current wpa_supplicant P2P support, but we did not yet support the
> > > P2P_DEVICE user-space API.
> > > 
> > > Last week I enabled that in brcmfmac testing it with wpa_supplicant
> > > patches for P2P_DEVICE support from David Spinadel. So I do have a
> > > couple of brcmfmac patches to make that work and would like to submit
> > > those for 3.9 although it is not strictly a bug fix. Would you consider
> > > taking these?
> > 
> > That doesn't sound to me like something that would be worthy of such
> > an exception.
> 
> Maybe just make a small patch to disable the other API, so we don't end
> up having to support both?

Maybe I misunderstood.  So brcmfmac currently supports a P2P API
that is not otherwise available and which we don't want to support
in the future?

-- 
John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.

Re: P2P support in brcmfmac

[Johannes Berg]

On Wed, 2013-03-27 at 08:44 -0400, John W. Linville wrote:
> On Wed, Mar 27, 2013 at 01:34:58PM +0100, Johannes Berg wrote:
> > On Wed, 2013-03-27 at 08:22 -0400, John W. Linville wrote:
> > > On Wed, Mar 27, 2013 at 12:51:35PM +0100, Arend van Spriel wrote:
> > > 
> > > > In 3.9 we introduced P2P support in brcmfmac which was functional using
> > > > current wpa_supplicant P2P support, but we did not yet support the
> > > > P2P_DEVICE user-space API.
> > > > 
> > > > Last week I enabled that in brcmfmac testing it with wpa_supplicant
> > > > patches for P2P_DEVICE support from David Spinadel. So I do have a
> > > > couple of brcmfmac patches to make that work and would like to submit
> > > > those for 3.9 although it is not strictly a bug fix. Would you consider
> > > > taking these?
> > > 
> > > That doesn't sound to me like something that would be worthy of such
> > > an exception.
> > 
> > Maybe just make a small patch to disable the other API, so we don't end
> > up having to support both?
> 
> Maybe I misunderstood.  So brcmfmac currently supports a P2P API
> that is not otherwise available and which we don't want to support
> in the future?

As I understand it, brcmfmac currently supports having a P2P device
*netdev*, which is of (wireless) type STATION (presumably), which isn't
something we want to support (well, I don't anyway, it's difficult to
discover for applications).

The "correct" way (the way I decided to implement this P2P device
concept in the upstreamtree ) is to have a P2P device *wireless dev*
which has no netdev associated -- this makes more sense since no data
frames are ever transmitted or received on a P2P device.

As I understand Arend, he was suggesting to put patches into 3.9 that
would move brcmfmac from the interim API with a netdev he had used for
testing to the final API that is actually implemented in 3.9 but before
the wpa_supplicant patches had no way to get used. Now those patches are
there in wpa_supplicant though (or well, on their way in)

johannes

Re: P2P support in brcmfmac

[John W. Linville]

On Wed, Mar 27, 2013 at 01:51:15PM +0100, Johannes Berg wrote:
> On Wed, 2013-03-27 at 08:44 -0400, John W. Linville wrote:
> > On Wed, Mar 27, 2013 at 01:34:58PM +0100, Johannes Berg wrote:
> > > On Wed, 2013-03-27 at 08:22 -0400, John W. Linville wrote:
> > > > On Wed, Mar 27, 2013 at 12:51:35PM +0100, Arend van Spriel wrote:
> > > > 
> > > > > In 3.9 we introduced P2P support in brcmfmac which was functional using
> > > > > current wpa_supplicant P2P support, but we did not yet support the
> > > > > P2P_DEVICE user-space API.
> > > > > 
> > > > > Last week I enabled that in brcmfmac testing it with wpa_supplicant
> > > > > patches for P2P_DEVICE support from David Spinadel. So I do have a
> > > > > couple of brcmfmac patches to make that work and would like to submit
> > > > > those for 3.9 although it is not strictly a bug fix. Would you consider
> > > > > taking these?
> > > > 
> > > > That doesn't sound to me like something that would be worthy of such
> > > > an exception.
> > > 
> > > Maybe just make a small patch to disable the other API, so we don't end
> > > up having to support both?
> > 
> > Maybe I misunderstood.  So brcmfmac currently supports a P2P API
> > that is not otherwise available and which we don't want to support
> > in the future?
> 
> As I understand it, brcmfmac currently supports having a P2P device
> *netdev*, which is of (wireless) type STATION (presumably), which isn't
> something we want to support (well, I don't anyway, it's difficult to
> discover for applications).
> 
> The "correct" way (the way I decided to implement this P2P device
> concept in the upstreamtree ) is to have a P2P device *wireless dev*
> which has no netdev associated -- this makes more sense since no data
> frames are ever transmitted or received on a P2P device.
> 
> As I understand Arend, he was suggesting to put patches into 3.9 that
> would move brcmfmac from the interim API with a netdev he had used for
> testing to the final API that is actually implemented in 3.9 but before
> the wpa_supplicant patches had no way to get used. Now those patches are
> there in wpa_supplicant though (or well, on their way in)

I see...in that case, a patch that disables the interim API seems appropriate.

John
-- 
John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.

Re: P2P support in brcmfmac

[Arend van Spriel]

On 03/27/2013 01:51 PM, Johannes Berg wrote:
> On Wed, 2013-03-27 at 08:44 -0400, John W. Linville wrote:
>> On Wed, Mar 27, 2013 at 01:34:58PM +0100, Johannes Berg wrote:
>>> On Wed, 2013-03-27 at 08:22 -0400, John W. Linville wrote:
>>>> On Wed, Mar 27, 2013 at 12:51:35PM +0100, Arend van Spriel wrote:
>>>>
>>>>> In 3.9 we introduced P2P support in brcmfmac which was functional using
>>>>> current wpa_supplicant P2P support, but we did not yet support the
>>>>> P2P_DEVICE user-space API.
>>>>>
>>>>> Last week I enabled that in brcmfmac testing it with wpa_supplicant
>>>>> patches for P2P_DEVICE support from David Spinadel. So I do have a
>>>>> couple of brcmfmac patches to make that work and would like to submit
>>>>> those for 3.9 although it is not strictly a bug fix. Would you consider
>>>>> taking these?
>>>>
>>>> That doesn't sound to me like something that would be worthy of such
>>>> an exception.
>>>
>>> Maybe just make a small patch to disable the other API, so we don't end
>>> up having to support both?
>>
>> Maybe I misunderstood.  So brcmfmac currently supports a P2P API
>> that is not otherwise available and which we don't want to support
>> in the future?
> 
> As I understand it, brcmfmac currently supports having a P2P device
> *netdev*, which is of (wireless) type STATION (presumably), which isn't
> something we want to support (well, I don't anyway, it's difficult to
> discover for applications).

It is a bit more subtle. After the merge window since 3.9-rc1 brcmfmac
supports to have a P2P device *wireless dev* WITH a netdev associated as
the old wpa_supplicant needed a network interface. However, this
interface is only created when the driver is loaded with a module
parameter p2pon set to 1.

So brcmfmac announces P2P_DEVICE support in wiphy information. This will
cause wpa_supplicant (with P2P device patches) to create a
*wireless_dev* interface of P2P_DEVICE type.

> The "correct" way (the way I decided to implement this P2P device
> concept in the upstreamtree ) is to have a P2P device *wireless dev*
> which has no netdev associated -- this makes more sense since no data
> frames are ever transmitted or received on a P2P device.

True and I made additional patches on top of 3.9-rc1 that add support
for creating the "correct" P2P device *wireless_dev* through user-space.

> As I understand Arend, he was suggesting to put patches into 3.9 that
> would move brcmfmac from the interim API with a netdev he had used for
> testing to the final API that is actually implemented in 3.9 but before
> the wpa_supplicant patches had no way to get used. Now those patches are
> there in wpa_supplicant though (or well, on their way in)

The interim patches went in 3.9-rc1 so they end up in 3.9 without
nl80211 user-space support. I am now suggesting to add that nl80211
user-space support for 3.9 as well. As you indicated you do not consider
this as an exception to the bugfix rule, I will have to look what
happens when the new wpa_supplicant (with P2P device patches) tries to
use the 3.9-rc1 brcmfmac.

Regards,
Arend

Re: P2P support in brcmfmac

[Johannes Berg]

On Wed, 2013-03-27 at 15:29 +0100, Arend van Spriel wrote:

> > As I understand it, brcmfmac currently supports having a P2P device
> > *netdev*, which is of (wireless) type STATION (presumably), which isn't
> > something we want to support (well, I don't anyway, it's difficult to
> > discover for applications).
> 
> It is a bit more subtle. After the merge window since 3.9-rc1 brcmfmac
> supports to have a P2P device *wireless dev* WITH a netdev associated as
> the old wpa_supplicant needed a network interface. 

Oh, funky, I had no idea.

> However, this
> interface is only created when the driver is loaded with a module
> parameter p2pon set to 1.

You could just remove the module parameter then?

> So brcmfmac announces P2P_DEVICE support in wiphy information. This will
> cause wpa_supplicant (with P2P device patches) to create a
> *wireless_dev* interface of P2P_DEVICE type.

Right, but this wouldn't work because you don't support the interface
creation, so it would really just be an attempt to create it?

> The interim patches went in 3.9-rc1 so they end up in 3.9 without
> nl80211 user-space support. I am now suggesting to add that nl80211
> user-space support for 3.9 as well. As you indicated you do not consider
> this as an exception to the bugfix rule, I will have to look what
> happens when the new wpa_supplicant (with P2P device patches) tries to
> use the 3.9-rc1 brcmfmac.

Or you could just remove the module parameter *and* advertisting the
P2P_DEVICE interface type, that would be a very small patch to "fix" the
API by disabling it for that kernel version. OTOH, I'm not sure if
that's a concern for you. For me, it wouldn't be a concern because we
mostly use compat-wireless anyway, but your situation might be
different.

johannes

Re: P2P support in brcmfmac

[Arend van Spriel]

On 03/27/2013 03:38 PM, Johannes Berg wrote:
> On Wed, 2013-03-27 at 15:29 +0100, Arend van Spriel wrote:
> 
>>> As I understand it, brcmfmac currently supports having a P2P device
>>> *netdev*, which is of (wireless) type STATION (presumably), which isn't
>>> something we want to support (well, I don't anyway, it's difficult to
>>> discover for applications).
>>
>> It is a bit more subtle. After the merge window since 3.9-rc1 brcmfmac
>> supports to have a P2P device *wireless dev* WITH a netdev associated as
>> the old wpa_supplicant needed a network interface. 
> 
> Oh, funky, I had no idea.
> 
>> However, this
>> interface is only created when the driver is loaded with a module
>> parameter p2pon set to 1.
> 
> You could just remove the module parameter then?
> 

It kind of depends what mix of kernel and wpa_supplicant an OEM or
distro would select. There may be use-cases where they would need p2pon
parameter to have P2P functionality.

>> So brcmfmac announces P2P_DEVICE support in wiphy information. This will
>> cause wpa_supplicant (with P2P device patches) to create a
>> *wireless_dev* interface of P2P_DEVICE type.
> 
> Right, but this wouldn't work because you don't support the interface
> creation, so it would really just be an attempt to create it?
> 

Sure. Just thought it would be better to avoid the attempt.

>> The interim patches went in 3.9-rc1 so they end up in 3.9 without
>> nl80211 user-space support. I am now suggesting to add that nl80211
>> user-space support for 3.9 as well. As you indicated you do not consider
>> this as an exception to the bugfix rule, I will have to look what
>> happens when the new wpa_supplicant (with P2P device patches) tries to
>> use the 3.9-rc1 brcmfmac.
> 
> Or you could just remove the module parameter *and* advertisting the
> P2P_DEVICE interface type, that would be a very small patch to "fix" the
> API by disabling it for that kernel version. OTOH, I'm not sure if
> that's a concern for you. For me, it wouldn't be a concern because we
> mostly use compat-wireless anyway, but your situation might be
> different.

That is indeed what I guessed the patch should look like, which would
make P2P unavailable for 3.9 regardless the wpa_supplicant version used.
But indeed there is always compat-drivers aka. compat-wireless so I am
not that concerned.

Gr. AvS

Re: P2P support in brcmfmac

[John W. Linville]

On Wed, Mar 27, 2013 at 03:54:35PM +0100, Arend van Spriel wrote:
> On 03/27/2013 03:38 PM, Johannes Berg wrote:

> > Or you could just remove the module parameter *and* advertisting the
> > P2P_DEVICE interface type, that would be a very small patch to "fix" the
> > API by disabling it for that kernel version. OTOH, I'm not sure if
> > that's a concern for you. For me, it wouldn't be a concern because we
> > mostly use compat-wireless anyway, but your situation might be
> > different.
> 
> That is indeed what I guessed the patch should look like, which would
> make P2P unavailable for 3.9 regardless the wpa_supplicant version used.
> But indeed there is always compat-drivers aka. compat-wireless so I am
> not that concerned.

I think this is the patch we need in order to avoid messy confusion later...

-- 
John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.