On 04/23/2013 06:42 PM, Johannes Berg wrote:
On Tue, 2013-04-23 at 07:50 -0700, Marcel Holtmann wrote:
+config CFG80211_ANDROID_P2P_HACK
+ bool "Android P2P netdevice hack"
+ depends on CFG80211
+ depends on !CFG80211_WEXT
+ help
+ Enable this option for Android P2P w/ P2P Device.
+
do you really think this is a good idea? Wouldn't it be better if
Android just gets its userspace fixed. This way, they never will and
you carry this workaround forever.
Well, I'm about 50/50 on whether to merge this. On the one hand, it's a
very simple patch to carry out of tree, on the other hand more than one
person will need it.
Here is one who needs it. I consider this patch as a temporary solution,
but it would be good to have it upstream. We would be using
compat-drivers to backport the upstream brcmfmac to the android kernel,
which also takes care of cfg80211.
Has anybody actually looked into what it would take to just fix
Android userspace to use nl80211 to bring up P2P. I just see tons of
#ifdef added to the kernel.
Yes, I did :-)
However, for any system running Jelly Bean that's not really an option,
and I have no idea if/how K-whatever is coming, so it might not be
possible there either. Additionally, fairly large changes are needed in
wpa_supplicant to actually support the P2P-Device with only nl82011
APIs.
If android is moving to 3.8 kernel with KLP (key lime pie), you could
say that it requires middleware/wifi-framework to deal with the new
kernel API. However, it mostly involves wpa_supplicant regardless of
using it on android or not. So this is more a wpa_supplicant P2P hack.
This gives us a transition path while making changes to the other parts
of the stack.
For 'selfish' reasons I am not opposed to this path ;-)
+ if (!dev
+#ifdef CONFIG_CFG80211_ANDROID_P2P_HACK
+ || (wdev->iftype == NL80211_IFTYPE_P2P_DEVICE &&
+ info->genlhdr->cmd != NL80211_CMD_SET_INTERFACE)
+#endif
+ ) {
mutex_unlock(&cfg80211_mutex);
if (rtnl)
rtnl_unlock();
And doing an #ifdef in the middle of if-clause doesn't ring any alarm
bells that this might be a really bad idea ;)
Well, I could put an #ifdef into each and every command instead which I
didn't want to, which incidentally is the reason for not allowing this
with WEXT, WEXT ioctls on the P2P-Device netdev just cause crashes :)
I dislike these kind of constructs as well so I would like this to be
made somewhat cleaner (conditional helper function?).
Basically this way also reduces the surface of this patch to make it
easier to use out of tree.
When I am looking at the USB gadget handling, I see a lot of progress
in establishing a standard kernel interface and changing Android
userspace to work with that instead.
"progress" doesn't really help, at least in this case it's pretty much
an either-or situation and changing the userspace will take a long time.
As long as changing the user-space is done eventually, right.
Gr. AvS
--
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
