Message-ID: <48B6C7EA.7080606@telenet.be> (sfid-20080828_174526_250368_58AEC815)
Date: Thu, 28 Aug 2008 17:44:42 +0200
From: Ian Schram <ischram@telenet.be>
MIME-Version: 1.0
To: Tomas Winkler <tomasw@gmail.com>
CC: Johannes Berg <johannes@sipsolutions.net>,
	linux-wireless <linux-wireless@vger.kernel.org>
Subject: Re: iwl5000 oopses
References: <1217937364.3603.37.camel@johannes.berg>	 <1217938927.3603.40.camel@johannes.berg>	 <1ba2fa240808050820j1aa0ae7cj11f2758caa5ba4df@mail.gmail.com>	 <1219919760.8434.5.camel@johannes.berg>	 <1ba2fa240808280439m3524d17cm63deebdfc0d5b9dd@mail.gmail.com>	 <1219925859.25321.10.camel@johannes.berg> <1ba2fa240808280752t4b41996au43bf4cb1a61b7967@mail.gmail.com>
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Tomas Winkler wrote:
> On Thu, Aug 28, 2008 at 3:17 PM, Johannes Berg
> <johannes@sipsolutions.net> wrote:
>> On Thu, 2008-08-28 at 14:39 +0300, Tomas Winkler wrote:
>>> On Thu, Aug 28, 2008 at 1:36 PM, Johannes Berg
>>> <johannes@sipsolutions.net> wrote:
>>>> On Tue, 2008-08-05 at 18:20 +0300, Tomas Winkler wrote:
>>>>> On Tue, Aug 5, 2008 at 3:22 PM, Johannes Berg <johannes@sipsolutions.net> wrote:
>>>>>>> This is kernel 2.6.27-rc1-00504-g2b12a4c-dirty
>>>>>> [  126.826663] iwlagn: Intel(R) Wireless WiFi Link AGN driver for Linux, 1.3.27kds
>>>>>> [  126.826947] iwlagn: Copyright(c) 2003-2008 Intel Corporation
>>>>>> [  126.828369] iwlagn: Detected Intel Wireless WiFi Link 5350AGN REV=0x24
>>>>>> [  126.848680] iwlagn: Tunable channels: 13 802.11bg, 24 802.11a channels
>>>>>> [  127.014564] firmware: requesting iwlwifi-5000-1.ucode
>>>>>> [  127.170640] iwlagn: Error wrong command queue 43 command id 0x6B
>>>>>> [  127.170832] ------------[ cut here ]------------
>>>>>> [  127.170884] kernel BUG at drivers/net/wireless/iwlwifi/iwl-tx.c:1163!
>>>>>> [  127.170941] Oops: Exception in kernel mode, sig: 5 [#1]
>>>> This is still happening with -rc4.
>>> I know, at least one regression.
>> Well, I guess for me the addition of the 5000 series code to the kernel
>> is the regression, without it I can use the machine just fine, just have
>> no wireless ;)
> 
> And when I say that driver is half backed because I'm not done
> cleaning bugs it's somehow not understood
> Instead of chasing bugs I have to spend time to fitght the system.
> Tomas
> --

Probably a good idea to not see this as
,,you vs system'' ..  Anyways that discussion is going on in other threads
perhaps we can focus on what has to be done about this bug.

what's known about this bug? ad where does it trigger? reproducible?

the error message clearly shows an invalid queue id (43 or 0x2b) where it should be
a number in the range of [0,4], this is multiqueue related?

the value in this error message was set by the driver, and then relayed by the ucode
in order to know which "command" this is a response to.

assuming there is no memory corruption, and the ucode is correct, ...

It might be set wrong. The value that is set is either the command queue, or a
tx_command queue which is determined by a call to skb_get_queue_mapping(skb)

might be nice to add some debug output documenting what this function is returning.


finally can i quickly ask why these macro's (that "encode" this queue id to the field in which it's passed to the ucode):
#define SEQ_TO_QUEUE(x)  ((x >> 8) & 0xbf)
#define QUEUE_TO_SEQ(x)  ((x & 0xbf) << 8)
use 0xbf, when according to the sourcecode comments it only uses the last 6 bits, hence i would
expect 0x3f. In QUEUE_TO_SEQ this msb should never be set .. so i wonder if there is a hack
i'm missing somewhere.