<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/net/mac80211, branch v3.2.79</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>mac80211: minstrel_ht: set default tx aggregation timeout to 0</title>
<updated>2016-04-01T00:54:34+00:00</updated>
<author>
<name>Felix Fietkau</name>
<email>nbd@openwrt.org</email>
</author>
<published>2016-02-18T18:49:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=19090c1839987a3e0a9c5263ef9a2f8bf6b6c3a4'/>
<id>19090c1839987a3e0a9c5263ef9a2f8bf6b6c3a4</id>
<content type='text'>
commit 7a36b930e6ed4702c866dc74a5ad07318a57c688 upstream.

The value 5000 was put here with the addition of the timeout field to
ieee80211_start_tx_ba_session. It was originally added in mac80211 to
save resources for drivers like iwlwifi, which only supports a limited
number of concurrent aggregation sessions.

Since iwlwifi does not use minstrel_ht and other drivers don't need
this, 0 is a better default - especially since there have been
recent reports of aggregation setup related issues reproduced with
ath9k. This should improve stability without causing any adverse
effects.

Acked-by: Avery Pennarun &lt;apenwarr@gmail.com&gt;
Signed-off-by: Felix Fietkau &lt;nbd@openwrt.org&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 7a36b930e6ed4702c866dc74a5ad07318a57c688 upstream.

The value 5000 was put here with the addition of the timeout field to
ieee80211_start_tx_ba_session. It was originally added in mac80211 to
save resources for drivers like iwlwifi, which only supports a limited
number of concurrent aggregation sessions.

Since iwlwifi does not use minstrel_ht and other drivers don't need
this, 0 is a better default - especially since there have been
recent reports of aggregation setup related issues reproduced with
ath9k. This should improve stability without causing any adverse
effects.

Acked-by: Avery Pennarun &lt;apenwarr@gmail.com&gt;
Signed-off-by: Felix Fietkau &lt;nbd@openwrt.org&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mac80211: fix use of uninitialised values in RX aggregation</title>
<updated>2016-04-01T00:54:31+00:00</updated>
<author>
<name>Chris Bainbridge</name>
<email>chris.bainbridge@gmail.com</email>
</author>
<published>2016-01-27T15:46:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ff452c63c02a683eaeb63174625c74010cdeda5b'/>
<id>ff452c63c02a683eaeb63174625c74010cdeda5b</id>
<content type='text'>
commit f39ea2690bd61efec97622c48323f40ed6e16317 upstream.

Use kzalloc instead of kmalloc for struct tid_ampdu_rx to
initialize the "removed" field (all others are initialized
manually). That fixes:

UBSAN: Undefined behaviour in net/mac80211/rx.c:932:29
load of value 2 is not a valid value for type '_Bool'
CPU: 3 PID: 1134 Comm: kworker/u16:7 Not tainted 4.5.0-rc1+ #265
Workqueue: phy0 rt2x00usb_work_rxdone
 0000000000000004 ffff880254a7ba50 ffffffff8181d866 0000000000000007
 ffff880254a7ba78 ffff880254a7ba68 ffffffff8188422d ffffffff8379b500
 ffff880254a7bab8 ffffffff81884747 0000000000000202 0000000348620032
Call Trace:
 [&lt;ffffffff8181d866&gt;] dump_stack+0x45/0x5f
 [&lt;ffffffff8188422d&gt;] ubsan_epilogue+0xd/0x40
 [&lt;ffffffff81884747&gt;] __ubsan_handle_load_invalid_value+0x67/0x70
 [&lt;ffffffff82227b4d&gt;] ieee80211_sta_reorder_release.isra.16+0x5ed/0x730
 [&lt;ffffffff8222ca14&gt;] ieee80211_prepare_and_rx_handle+0xd04/0x1c00
 [&lt;ffffffff8222db03&gt;] __ieee80211_rx_handle_packet+0x1f3/0x750
 [&lt;ffffffff8222e4a7&gt;] ieee80211_rx_napi+0x447/0x990

While at it, convert to use sizeof(*tid_agg_rx) instead.

Fixes: 788211d81bfdf ("mac80211: fix RX A-MPDU session reorder timer deletion")
Signed-off-by: Chris Bainbridge &lt;chris.bainbridge@gmail.com&gt;
[reword commit message, use sizeof(*tid_agg_rx)]
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit f39ea2690bd61efec97622c48323f40ed6e16317 upstream.

Use kzalloc instead of kmalloc for struct tid_ampdu_rx to
initialize the "removed" field (all others are initialized
manually). That fixes:

UBSAN: Undefined behaviour in net/mac80211/rx.c:932:29
load of value 2 is not a valid value for type '_Bool'
CPU: 3 PID: 1134 Comm: kworker/u16:7 Not tainted 4.5.0-rc1+ #265
Workqueue: phy0 rt2x00usb_work_rxdone
 0000000000000004 ffff880254a7ba50 ffffffff8181d866 0000000000000007
 ffff880254a7ba78 ffff880254a7ba68 ffffffff8188422d ffffffff8379b500
 ffff880254a7bab8 ffffffff81884747 0000000000000202 0000000348620032
Call Trace:
 [&lt;ffffffff8181d866&gt;] dump_stack+0x45/0x5f
 [&lt;ffffffff8188422d&gt;] ubsan_epilogue+0xd/0x40
 [&lt;ffffffff81884747&gt;] __ubsan_handle_load_invalid_value+0x67/0x70
 [&lt;ffffffff82227b4d&gt;] ieee80211_sta_reorder_release.isra.16+0x5ed/0x730
 [&lt;ffffffff8222ca14&gt;] ieee80211_prepare_and_rx_handle+0xd04/0x1c00
 [&lt;ffffffff8222db03&gt;] __ieee80211_rx_handle_packet+0x1f3/0x750
 [&lt;ffffffff8222e4a7&gt;] ieee80211_rx_napi+0x447/0x990

While at it, convert to use sizeof(*tid_agg_rx) instead.

Fixes: 788211d81bfdf ("mac80211: fix RX A-MPDU session reorder timer deletion")
Signed-off-by: Chris Bainbridge &lt;chris.bainbridge@gmail.com&gt;
[reword commit message, use sizeof(*tid_agg_rx)]
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mac80211: mesh: fix call_rcu() usage</title>
<updated>2015-12-30T02:25:56+00:00</updated>
<author>
<name>Johannes Berg</name>
<email>johannes.berg@intel.com</email>
</author>
<published>2015-11-17T13:25:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4fffe0aafb9c3ac37c74026275cba43fefa6cd0e'/>
<id>4fffe0aafb9c3ac37c74026275cba43fefa6cd0e</id>
<content type='text'>
commit c2e703a55245bfff3db53b1f7cbe59f1ee8a4339 upstream.

When using call_rcu(), the called function may be delayed quite
significantly, and without a matching rcu_barrier() there's no
way to be sure it has finished.
Therefore, global state that could be gone/freed/reused should
never be touched in the callback.

Fix this in mesh by moving the atomic_dec() into the caller;
that's not really a problem since we already unlinked the path
and it will be destroyed anyway.

This fixes a crash Jouni observed when running certain tests in
a certain order, in which the mesh interface was torn down, the
memory reused for a function pointer (work struct) and running
that then crashed since the pointer had been decremented by 1,
resulting in an invalid instruction byte stream.

Fixes: eb2b9311fd00 ("mac80211: mesh path table implementation")
Reported-by: Jouni Malinen &lt;j@w1.fi&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c2e703a55245bfff3db53b1f7cbe59f1ee8a4339 upstream.

When using call_rcu(), the called function may be delayed quite
significantly, and without a matching rcu_barrier() there's no
way to be sure it has finished.
Therefore, global state that could be gone/freed/reused should
never be touched in the callback.

Fix this in mesh by moving the atomic_dec() into the caller;
that's not really a problem since we already unlinked the path
and it will be destroyed anyway.

This fixes a crash Jouni observed when running certain tests in
a certain order, in which the mesh interface was torn down, the
memory reused for a function pointer (work struct) and running
that then crashed since the pointer had been decremented by 1,
resulting in an invalid instruction byte stream.

Fixes: eb2b9311fd00 ("mac80211: mesh path table implementation")
Reported-by: Jouni Malinen &lt;j@w1.fi&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mac80211: fix driver RSSI event calculations</title>
<updated>2015-11-27T12:48:19+00:00</updated>
<author>
<name>Johannes Berg</name>
<email>johannes.berg@intel.com</email>
</author>
<published>2015-08-28T08:52:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=adc82592cde76e5d6182c66bf0c67560f0ee0abf'/>
<id>adc82592cde76e5d6182c66bf0c67560f0ee0abf</id>
<content type='text'>
commit 8ec6d97871f37e4743678ea4a455bd59580aa0f4 upstream.

The ifmgd-&gt;ave_beacon_signal value cannot be taken as is for
comparisons, it must be divided by since it's represented
like that for better accuracy of the EWMA calculations. This
would lead to invalid driver RSSI events. Fix the used value.

Fixes: 615f7b9bb1f8 ("mac80211: add driver RSSI threshold events")
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 8ec6d97871f37e4743678ea4a455bd59580aa0f4 upstream.

The ifmgd-&gt;ave_beacon_signal value cannot be taken as is for
comparisons, it must be divided by since it's represented
like that for better accuracy of the EWMA calculations. This
would lead to invalid driver RSSI events. Fix the used value.

Fixes: 615f7b9bb1f8 ("mac80211: add driver RSSI threshold events")
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mac80211: enable assoc check for mesh interfaces</title>
<updated>2015-10-13T02:46:04+00:00</updated>
<author>
<name>Bob Copeland</name>
<email>me@bobcopeland.com</email>
</author>
<published>2015-06-13T14:16:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a661308ed4fd046ce6fe74a24e64f002f7930758'/>
<id>a661308ed4fd046ce6fe74a24e64f002f7930758</id>
<content type='text'>
commit 3633ebebab2bbe88124388b7620442315c968e8f upstream.

We already set a station to be associated when peering completes, both
in user space and in the kernel.  Thus we should always have an
associated sta before sending data frames to that station.

Failure to check assoc state can cause crashes in the lower-level driver
due to transmitting unicast data frames before driver sta structures
(e.g. ampdu state in ath9k) are initialized.  This occurred when
forwarding in the presence of fixed mesh paths: frames were transmitted
to stations with whom we hadn't yet completed peering.

Reported-by: Alexis Green &lt;agreen@cococorp.com&gt;
Tested-by: Jesse Jones &lt;jjones@cococorp.com&gt;
Signed-off-by: Bob Copeland &lt;me@bobcopeland.com&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 3633ebebab2bbe88124388b7620442315c968e8f upstream.

We already set a station to be associated when peering completes, both
in user space and in the kernel.  Thus we should always have an
associated sta before sending data frames to that station.

Failure to check assoc state can cause crashes in the lower-level driver
due to transmitting unicast data frames before driver sta structures
(e.g. ampdu state in ath9k) are initialized.  This occurred when
forwarding in the presence of fixed mesh paths: frames were transmitted
to stations with whom we hadn't yet completed peering.

Reported-by: Alexis Green &lt;agreen@cococorp.com&gt;
Tested-by: Jesse Jones &lt;jjones@cococorp.com&gt;
Signed-off-by: Bob Copeland &lt;me@bobcopeland.com&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mac80211: clear subdir_stations when removing debugfs</title>
<updated>2015-08-12T14:33:22+00:00</updated>
<author>
<name>Tom Hughes</name>
<email>tom@compton.nu</email>
</author>
<published>2015-06-29T18:41:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=77f807e34765258d91104c61f2a3bf64d4c3477b'/>
<id>77f807e34765258d91104c61f2a3bf64d4c3477b</id>
<content type='text'>
commit 4479004e6409087d1b4986881dc98c6c15dffb28 upstream.

If we don't do this, and we then fail to recreate the debugfs
directory during a mode change, then we will fail later trying
to add stations to this now bogus directory:

BUG: unable to handle kernel NULL pointer dereference at 0000006c
IP: [&lt;c0a92202&gt;] mutex_lock+0x12/0x30
Call Trace:
[&lt;c0678ab4&gt;] start_creating+0x44/0xc0
[&lt;c0679203&gt;] debugfs_create_dir+0x13/0xf0
[&lt;f8a938ae&gt;] ieee80211_sta_debugfs_add+0x6e/0x490 [mac80211]

Signed-off-by: Tom Hughes &lt;tom@compton.nu&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 4479004e6409087d1b4986881dc98c6c15dffb28 upstream.

If we don't do this, and we then fail to recreate the debugfs
directory during a mode change, then we will fail later trying
to add stations to this now bogus directory:

BUG: unable to handle kernel NULL pointer dereference at 0000006c
IP: [&lt;c0a92202&gt;] mutex_lock+0x12/0x30
Call Trace:
[&lt;c0678ab4&gt;] start_creating+0x44/0xc0
[&lt;c0679203&gt;] debugfs_create_dir+0x13/0xf0
[&lt;f8a938ae&gt;] ieee80211_sta_debugfs_add+0x6e/0x490 [mac80211]

Signed-off-by: Tom Hughes &lt;tom@compton.nu&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mac80211: move WEP tailroom size check</title>
<updated>2015-08-06T23:32:10+00:00</updated>
<author>
<name>Janusz Dziedzic</name>
<email>janusz.dziedzic@tieto.com</email>
</author>
<published>2015-05-11T09:31:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=06b9576ec258ff39f0f95a226c49a03d7aca68a1'/>
<id>06b9576ec258ff39f0f95a226c49a03d7aca68a1</id>
<content type='text'>
commit 47b4e1fc4972cc43a19121bc2608a60aef3bf216 upstream.

Remove checking tailroom when adding IV as it uses only
headroom, and move the check to the ICV generation that
actually needs the tailroom.

In other case I hit such warning and datapath don't work,
when testing:
- IBSS + WEP
- ath9k with hw crypt enabled
- IPv6 data (ping6)

WARNING: CPU: 3 PID: 13301 at net/mac80211/wep.c:102 ieee80211_wep_add_iv+0x129/0x190 [mac80211]()
[...]
Call Trace:
[&lt;ffffffff817bf491&gt;] dump_stack+0x45/0x57
[&lt;ffffffff8107746a&gt;] warn_slowpath_common+0x8a/0xc0
[&lt;ffffffff8107755a&gt;] warn_slowpath_null+0x1a/0x20
[&lt;ffffffffc09ae109&gt;] ieee80211_wep_add_iv+0x129/0x190 [mac80211]
[&lt;ffffffffc09ae7ab&gt;] ieee80211_crypto_wep_encrypt+0x6b/0xd0 [mac80211]
[&lt;ffffffffc09d3fb1&gt;] invoke_tx_handlers+0xc51/0xf30 [mac80211]
[...]

Signed-off-by: Janusz Dziedzic &lt;janusz.dziedzic@tieto.com&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
[bwh: Backported to 3.2: s/IEEE80211_WEP/WEP/]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 47b4e1fc4972cc43a19121bc2608a60aef3bf216 upstream.

Remove checking tailroom when adding IV as it uses only
headroom, and move the check to the ICV generation that
actually needs the tailroom.

In other case I hit such warning and datapath don't work,
when testing:
- IBSS + WEP
- ath9k with hw crypt enabled
- IPv6 data (ping6)

WARNING: CPU: 3 PID: 13301 at net/mac80211/wep.c:102 ieee80211_wep_add_iv+0x129/0x190 [mac80211]()
[...]
Call Trace:
[&lt;ffffffff817bf491&gt;] dump_stack+0x45/0x57
[&lt;ffffffff8107746a&gt;] warn_slowpath_common+0x8a/0xc0
[&lt;ffffffff8107755a&gt;] warn_slowpath_null+0x1a/0x20
[&lt;ffffffffc09ae109&gt;] ieee80211_wep_add_iv+0x129/0x190 [mac80211]
[&lt;ffffffffc09ae7ab&gt;] ieee80211_crypto_wep_encrypt+0x6b/0xd0 [mac80211]
[&lt;ffffffffc09d3fb1&gt;] invoke_tx_handlers+0xc51/0xf30 [mac80211]
[...]

Signed-off-by: Janusz Dziedzic &lt;janusz.dziedzic@tieto.com&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
[bwh: Backported to 3.2: s/IEEE80211_WEP/WEP/]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mac80211: fix RX A-MPDU session reorder timer deletion</title>
<updated>2015-05-09T22:16:34+00:00</updated>
<author>
<name>Johannes Berg</name>
<email>johannes.berg@intel.com</email>
</author>
<published>2015-04-01T12:20:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e879f0ef6ea3e5cad8e01572840825dfe6436568'/>
<id>e879f0ef6ea3e5cad8e01572840825dfe6436568</id>
<content type='text'>
commit 788211d81bfdf9b6a547d0530f206ba6ee76b107 upstream.

There's an issue with the way the RX A-MPDU reorder timer is
deleted that can cause a kernel crash like this:

 * tid_rx is removed - call_rcu(ieee80211_free_tid_rx)
 * station is destroyed
 * reorder timer fires before ieee80211_free_tid_rx() runs,
   accessing the station, thus potentially crashing due to
   the use-after-free

The station deletion is protected by synchronize_net(), but
that isn't enough -- ieee80211_free_tid_rx() need not have
run when that returns (it deletes the timer.) We could use
rcu_barrier() instead of synchronize_net(), but that's much
more expensive.

Instead, to fix this, add a field tracking that the session
is being deleted. In this case, the only re-arming of the
timer happens with the reorder spinlock held, so make that
code not rearm it if the session is being deleted and also
delete the timer after setting that field. This ensures the
timer cannot fire after ___ieee80211_stop_rx_ba_session()
returns, which fixes the problem.

Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 788211d81bfdf9b6a547d0530f206ba6ee76b107 upstream.

There's an issue with the way the RX A-MPDU reorder timer is
deleted that can cause a kernel crash like this:

 * tid_rx is removed - call_rcu(ieee80211_free_tid_rx)
 * station is destroyed
 * reorder timer fires before ieee80211_free_tid_rx() runs,
   accessing the station, thus potentially crashing due to
   the use-after-free

The station deletion is protected by synchronize_net(), but
that isn't enough -- ieee80211_free_tid_rx() need not have
run when that returns (it deletes the timer.) We could use
rcu_barrier() instead of synchronize_net(), but that's much
more expensive.

Instead, to fix this, add a field tracking that the session
is being deleted. In this case, the only re-arming of the
timer happens with the reorder spinlock held, so make that
code not rearm it if the session is being deleted and also
delete the timer after setting that field. This ensures the
timer cannot fire after ___ieee80211_stop_rx_ba_session()
returns, which fixes the problem.

Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mac80211: disable u-APSD queues by default</title>
<updated>2015-05-09T22:16:26+00:00</updated>
<author>
<name>Michal Kazior</name>
<email>michal.kazior@tieto.com</email>
</author>
<published>2015-02-10T11:48:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=711077a666f760b9c7c266725b4a5ec804248ebe'/>
<id>711077a666f760b9c7c266725b4a5ec804248ebe</id>
<content type='text'>
commit aa75ebc275b2a91b193654a177daf900ad6703f0 upstream.

Some APs experience problems when working with
U-APSD. Decreasing the probability of that
happening by using legacy mode for all ACs but VO
isn't enough.

Cisco 4410N originally forced us to enable VO by
default only because it treated non-VO ACs as
legacy.

However some APs (notably Netgear R7000) silently
reclassify packets to different ACs. Since u-APSD
ACs require trigger frames for frame retrieval
clients would never see some frames (e.g. ARP
responses) or would fetch them accidentally after
a long time.

It makes little sense to enable u-APSD queues by
default because it needs userspace applications to
be aware of it to actually take advantage of the
possible additional powersavings. Implicitly
depending on driver autotrigger frame support
doesn't make much sense.

Signed-off-by: Michal Kazior &lt;michal.kazior@tieto.com&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit aa75ebc275b2a91b193654a177daf900ad6703f0 upstream.

Some APs experience problems when working with
U-APSD. Decreasing the probability of that
happening by using legacy mode for all ACs but VO
isn't enough.

Cisco 4410N originally forced us to enable VO by
default only because it treated non-VO ACs as
legacy.

However some APs (notably Netgear R7000) silently
reclassify packets to different ACs. Since u-APSD
ACs require trigger frames for frame retrieval
clients would never see some frames (e.g. ARP
responses) or would fetch them accidentally after
a long time.

It makes little sense to enable u-APSD queues by
default because it needs userspace applications to
be aware of it to actually take advantage of the
possible additional powersavings. Implicitly
depending on driver autotrigger frame support
doesn't make much sense.

Signed-off-by: Michal Kazior &lt;michal.kazior@tieto.com&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mac80211: set only VO as a U-APSD enabled AC</title>
<updated>2015-05-09T22:16:26+00:00</updated>
<author>
<name>Arik Nemtsov</name>
<email>arik@wizery.com</email>
</author>
<published>2012-06-18T07:43:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9a640c0a30fa30022060eaa2908589ffd7cfbc1f'/>
<id>9a640c0a30fa30022060eaa2908589ffd7cfbc1f</id>
<content type='text'>
commit d6a4ed6fe0a0d4790941e7f13e56630b8b9b053d upstream.

Some APs experience problems when working with U-APSD. Decrease the
probability of that happening by using legacy mode for all ACs but VO.

The AP that caused us troubles was a Cisco 4410N. It ignores our
setting, and always treats non-VO ACs as legacy.

Signed-off-by: Arik Nemtsov &lt;arik@wizery.com&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit d6a4ed6fe0a0d4790941e7f13e56630b8b9b053d upstream.

Some APs experience problems when working with U-APSD. Decrease the
probability of that happening by using legacy mode for all ACs but VO.

The AP that caused us troubles was a Cisco 4410N. It ignores our
setting, and always treats non-VO ACs as legacy.

Signed-off-by: Arik Nemtsov &lt;arik@wizery.com&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
</feed>
