Subject: RTL8192CU on ARM not working

From: [email-masked] (Maxime Ripard)
Date: Fri, 28 Jun 2013 15:40:08 +0200

Hi Richard, Larry,

On Thu, Jun 27, 2013 at 02:13:31PM +0200, Richard Genoud wrote:
> 2013/6/27 Maxime Ripard <[email-masked]>:
> > Hi everyone,
> >
> > I'm currently trying to use a RTL8192CU on an ARM (Freescale imx28,
> > armv5) platform, using 3.10-rc3.
> >
> > Trouble is, while the chip is correctly detected and you can use iw on it
> > without any problem it seems, once you start an association to an access
> > point, the association goes on, seems to associate, displaying a WARN()
> > message [1] and then, after what looks like a random amount of time (could
> > be right away, could be after a few minutes), deassociate [2].
> >
> > During the time where it's associated, we never seem to transmit any
> > packets, while iw reports packets being sent, I guess we can assume that
> > they are actually never transmitted as well [3].
> >
> > What seems odd to me as well is that the signal power reported for the access
> > point is excessively high when using iw scan (10 dbm), and once connected, the
> > signal strength is -64dbm, which makes quite a huge difference.
> >
> > Do you have any suggestions on how to solve this issue?
> >
> > Thanks,
> > Maxime
> >
> >
> > [1]:
> > # iw wlan0 connect FreeWifi 2447
> > # [  485.010858] wlan0: authenticate with f4:ca:e5:c9:f5:91
> > [  485.065514] wlan0: send auth to f4:ca:e5:c9:f5:91 (try 1/3)
> > [  485.075963] wlan0: authenticated
> > [  485.088915] wlan0: associate with f4:ca:e5:c9:f5:91 (try 1/3)
> > [  485.117137] wlan0: RX AssocResp from f4:ca:e5:c9:f5:91 (capab=0x401 status=0 aid=1)
> > [  485.130607] wlan0: associated
> > [  486.917555] ------------[ cut here ]------------
> > [  486.922277] WARNING: at kernel/workqueue.c:1365 __queue_work+0x1f0/0x2f4()
> > [  486.929175] Modules linked in:
> > [  486.932284] CPU: 0 PID: 615 Comm: kworker/0:2 Not tainted 3.10.0-rc3 #2
> > [  486.938958] Workqueue: rtl92c_usb rtl_watchdog_wq_callback
> > [  486.944548] [<c00147dc>] (unwind_backtrace+0x0/0xf0) from [<c00120a0>] (show_stack+0x10/0x14)
> > [  486.953132] [<c00120a0>] (show_stack+0x10/0x14) from [<c001d2ec>] (warn_slowpath_common+0x4c/0x68)
> > [  486.962140] [<c001d2ec>] (warn_slowpath_common+0x4c/0x68) from [<c001d324>] (warn_slowpath_null+0x1c/0x24)
> > [  486.971844] [<c001d324>] (warn_slowpath_null+0x1c/0x24) from [<c003769c>] (__queue_work+0x1f0/0x2f4)
> > [  486.981025] [<c003769c>] (__queue_work+0x1f0/0x2f4) from [<c0037830>] (queue_work_on+0x80/0x88)
> > [  486.989777] [<c0037830>] (queue_work_on+0x80/0x88) from [<c0267ca4>] (rtl_watchdog_wq_callback+0x5dc/0x8bc)
> > [  486.999572] [<c0267ca4>] (rtl_watchdog_wq_callback+0x5dc/0x8bc) from [<c0038cbc>] (process_one_work+0x1c0/0x4c8)
> > [  487.009795] [<c0038cbc>] (process_one_work+0x1c0/0x4c8) from [<c0039684>] (worker_thread+0x140/0x3ac)
> > [  487.019065] [<c0039684>] (worker_thread+0x140/0x3ac) from [<c003f914>] (kthread+0xa4/0xb0)
> > [  487.027381] [<c003f914>] (kthread+0xa4/0xb0) from [<c000f0c0>] (ret_from_fork+0x14/0x34)
> > [  487.035498] ---[ end trace 93341a0c249e647e ]---
> >
> >
> > [2]:
> >
> > # [  786.086127] wlan0: deauthenticated from f4:ca:e5:c9:f5:91 (Reason: 2)
> > [  786.126368] cfg80211: Calling CRDA to update world regulatory domain
> >
> >
> > [3]:
> > # iw wlan0 station dump
> > Station f4:ca:e5:c9:f5:91 (on wlan0)
> >         inactive time:  55430 ms
> >         rx bytes:       77826
> >         rx packets:     1026
> >         tx packets:     2
> >         tx retries:     0
> >         tx failed:      0
> >         signal:         -64 dBm
> >         signal avg:     -63 dBm
> >         tx bitrate:     1.0 MBit/s
> >         authorized:     yes
> >         authenticated:  yes
> >         preamble:       long
> >         WMM/WME:        yes
> >         MFP:            no
> >         TDLS peer:      no
> 
> Hi Maxime,
> 
> You should have a look at https://lkml.org/lkml/2013/6/11/300
> (in short, use 3.10-rc7)
> 
> The warning is still there, but I managed use this device on ARM
> (sam9g35) as a client.

Indeed, the client mode works way better with 3.10-rc7.

Thanks to you two!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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