I'm not wireless expert but, after reading a bit and analysing your syslog output:
----
Aug 20 12:57:16 martin04 kernel: [ 9464.423445] Call Trace:
Aug 20 12:57:16 martin04 kernel: [ 9464.423451] [<ffffffff817aeed7>] dump_stack+0x45/0x57
Aug 20 12:57:16 martin04 kernel: [ 9464.423453] [<ffffffff81074d8a>] warn_slowpath_common+0x8a/0xc0
Aug 20 12:57:16 martin04 kernel: [ 9464.423455] [<ffffffff81074e7a>] warn_slowpath_null+0x1a/0x20
Aug 20 12:57:16 martin04 kernel: [ 9464.423462] [<ffffffffc04c5e09>] cfg80211_roamed+0x89/0x90 [cfg80211]
Aug 20 12:57:16 martin04 kernel: [ 9464.423489] [<ffffffffc07aba0b>] wl_notify_roaming_status+0xcb/0x150 [wl]
Aug 20 12:57:16 martin04 kernel: [ 9464.423508] [<ffffffffc07a876a>] wl_event_handler+0x6a/0x230 [wl]
Aug 20 12:57:16 martin04 kernel: [ 9464.423526] [<ffffffffc07a8700>] ? wl_free_wdev.isra.23+0x80/0x80 [wl]
Aug 20 12:57:16 martin04 kernel: [ 9464.423529] [<ffffffff81093802>] kthread+0xd2/0xf0
Aug 20 12:57:16 martin04 kernel: [ 9464.423531] [<ffffffff81093730>] ? kthread_create_on_node+0x1c0/0x1c0
Aug 20 12:57:16 martin04 kernel: [ 9464.423533] [<ffffffff817b67d8>] ret_from_fork+0x58/0x90
Aug 20 12:57:16 martin04 kernel: [ 9464.423535] [<ffffffff81093730>] ? kthread_create_on_node+0x1c0/0x1c0
----
This only means that broadcom WL driver tried to warn kernel that it roamed from one AP to another and new BSS could not be found (meaning that the card could not get all its new BSS - peers, APs, etc).
*** Try configuring the wireless adapter to use a SPECIFIC AP *** and check your wifi env for interferences that might be stepping into broadcom's driver decisions on whether to roam or not -> This does not mean a fix for WL is not needed, it only means we would have to wait for Broadcom to come up with a new driver.
Based on good feedback from Igor I'll suggest fixes for all Ubuntu versions. Even if upstream BW driver still faces problems with adapters, we still have to fix this bug's original problem.
I'll attach debdiffs for this bug soon.
Alberto,
I saw you pushed precise into latest version (right now in -proposed), I'll check if it also needs the fix and provide debdiff. Let me know if you have any other comments since you've been handling all bcmwl work and you are more into it than I am.
Martin,
I'm not wireless expert but, after reading a bit and analysing your syslog output:
---- ed7>] dump_stack+ 0x45/0x57 d8a>] warn_slowpath_ common+ 0x8a/0xc0 e7a>] warn_slowpath_ null+0x1a/ 0x20 e09>] cfg80211_ roamed+ 0x89/0x90 [cfg80211] a0b>] wl_notify_ roaming_ status+ 0xcb/0x150 [wl] 76a>] wl_event_ handler+ 0x6a/0x230 [wl] 700>] ? wl_free_ wdev.isra. 23+0x80/ 0x80 [wl] 802>] kthread+0xd2/0xf0 730>] ? kthread_ create_ on_node+ 0x1c0/0x1c0 7d8>] ret_from_ fork+0x58/ 0x90 730>] ? kthread_ create_ on_node+ 0x1c0/0x1c0
Aug 20 12:57:16 martin04 kernel: [ 9464.423445] Call Trace:
Aug 20 12:57:16 martin04 kernel: [ 9464.423451] [<ffffffff817ae
Aug 20 12:57:16 martin04 kernel: [ 9464.423453] [<ffffffff81074
Aug 20 12:57:16 martin04 kernel: [ 9464.423455] [<ffffffff81074
Aug 20 12:57:16 martin04 kernel: [ 9464.423462] [<ffffffffc04c5
Aug 20 12:57:16 martin04 kernel: [ 9464.423489] [<ffffffffc07ab
Aug 20 12:57:16 martin04 kernel: [ 9464.423508] [<ffffffffc07a8
Aug 20 12:57:16 martin04 kernel: [ 9464.423526] [<ffffffffc07a8
Aug 20 12:57:16 martin04 kernel: [ 9464.423529] [<ffffffff81093
Aug 20 12:57:16 martin04 kernel: [ 9464.423531] [<ffffffff81093
Aug 20 12:57:16 martin04 kernel: [ 9464.423533] [<ffffffff817b6
Aug 20 12:57:16 martin04 kernel: [ 9464.423535] [<ffffffff81093
----
This only means that broadcom WL driver tried to warn kernel that it roamed from one AP to another and new BSS could not be found (meaning that the card could not get all its new BSS - peers, APs, etc).
*** Try configuring the wireless adapter to use a SPECIFIC AP *** and check your wifi env for interferences that might be stepping into broadcom's driver decisions on whether to roam or not -> This does not mean a fix for WL is not needed, it only means we would have to wait for Broadcom to come up with a new driver.
Based on good feedback from Igor I'll suggest fixes for all Ubuntu versions. Even if upstream BW driver still faces problems with adapters, we still have to fix this bug's original problem.
I'll attach debdiffs for this bug soon.
Alberto,
I saw you pushed precise into latest version (right now in -proposed), I'll check if it also needs the fix and provide debdiff. Let me know if you have any other comments since you've been handling all bcmwl work and you are more into it than I am.
Thank you
Rafael