Re: Re: Reliable unreliability with D-Link DWL-122 USB

Over on the devel alias we are discussing this too.

>From what I can gather, there appears to be no
certain way of avoiding a network lockup with the
prism cards other than garunteeing that nothing
reads /proc/bus/usb/devices. It would seem that this
is just a nasty bug in the prism cards themselves
(presumably they cannot safely handle the control-endpoint-0
messages at the same time as normal messages on their
endpoints 1 & 2).

However, its not all bad news. The main culprit seems
to be hald, which in versions before 0.5.0 is regularly
reading /proc/bus/usb/devices and thus making the lockup
highly likely. As far as I can see from the hal source
code, a major change in 0.5.0 might remove this behaviour -
it will do the lookup only the once rather than frequently.
Unfortunately I don't have the time or the wits to try
and upgrade my system to test this theory.

However I do intend to try a patch to 0.4.7 to see if I can
make it not read frequently (possibly at the expense of
some of its functionality that I most likely do not
use anyway). If that works, I'll post the info.

Karl

> 
> From: Dave Jenkins <[email protected]>
> Date: 2005/05/28 Sat PM 07:57:05 GMT
> To: [email protected]
> Subject: Re: [lwlan-user] Reliable unreliability with D-Link DWL-122 USB
> 
> --- Holger Wansing <[email protected]> wrote:
> > The only problem I know about is, that the stick
> > fails to work,
> > if any process (as hal for example) scans the
> > /proc/bus/usb/devices
> > file. In this case the stick hangs up with many
> > problems for
> > getting it to work again.
> 
> Thanks for the reply, Holger. I've just experimented
> with reading /proc/bus/usb/devices a few times while
> using the network and it reproduces the error that I
> described, i.e. wlan stops working and I get:
> 
> kernel: hfa384x_usbin_ctlx: Could not match IN
> URB(0x8001,0) to CTLX - ignored
> 
> Sometimes I also get further errors - details at the
> bottom of this mail.
> 
> I am able to recover from this error as I described in
> my previous mail, by ifdown wlan0 and modprobe -r
> wlan0 followed by either modprobe wlan0 or unplugging
> and replugging the adaptor.
> 
> I have hald running, so maybe it is reading
> /proc/bus/usb/devices during boot and causing the
> once-per-boot problem that I'm seeing.
> 
> That seems like progress! Where do we go from here?
> Are there any developers on the list who can suggest
> where a solution might lie - if it's a hardware issue,
> might there be a workaround?
> 
> Cheers,
> 
> Dave
> 
> Details of the further errors that I sometimes get:
> This is on Fedora Core 3 with kernel 2.6.11-1.27_FC3,
> Via KM400 chipset.
> ------8<------
> May 28 20:20:00 bagpuss kernel: NETDEV WATCHDOG:
> wlan0: transmit timed out
> May 28 20:20:00 bagpuss kernel: usb_unlink_urb() is
> deprecated for synchronous unlinks.  Use
> usb_kill_urb() instead.
> May 28 20:20:00 bagpuss kernel: Badness in
> usb_unlink_urb at drivers/usb/core/urb.c:457 (Not
> tainted)
> May 28 20:20:00 bagpuss kernel:  [<c02c0730>]
> usb_unlink_urb+0x98/0x9a
> May 28 20:20:00 bagpuss kernel:  [<de903604>]
> hfa384x_usb_defer+0x174/0x2f7 [prism2_usb]
> May 28 20:20:00 bagpuss kernel:  [<c01357e2>]
> worker_thread+0x1c4/0x415
> May 28 20:20:00 bagpuss kernel:  [<de903490>]
> hfa384x_usb_defer+0x0/0x2f7 [prism2_usb]
> May 28 20:20:00 bagpuss kernel:  [<c011aac8>]
> default_wake_function+0x0/0xc
> May 28 20:20:00 bagpuss kernel:  [<c011aac8>]
> default_wake_function+0x0/0xc
> May 28 20:20:00 bagpuss kernel:  [<c013561e>]
> worker_thread+0x0/0x415
> May 28 20:20:00 bagpuss kernel:  [<c013b930>]
> kthread+0x7c/0xa4
> May 28 20:20:00 bagpuss kernel:  [<c013b8b4>]
> kthread+0x0/0xa4
> May 28 20:20:00 bagpuss kernel:  [<c0101291>]
> kernel_thread_helper+0x5/0xb
> May 28 20:20:00 bagpuss kernel: wlan0 rx pipe reset
> complete.
> ------8<------
> 
> 
> 		
> ___________________________________________________________ 
> How much free photo storage do you get? Store your holiday 
> snaps for FREE with Yahoo! Photos http://uk.photos.yahoo.com
> _______________________________________________
> Linux-wlan-user mailing list
> [email protected]
> http://lists.linux-wlan.com/mailman/listinfo/linux-wlan-user
> 

-----------------------------------------
Email sent from www.ntlworld.com
virus-checked using McAfee(R) Software
visit www.ntlworld.com/security for more information