Re: [rt2x00-users] ieee80211_tx_status: headroom too small

From: David Ellingsworth
Date: Sun Nov 22 2009 - 02:14:51 EST


On Sat, Nov 21, 2009 at 10:27 AM, Gertjan van Wingerde
<gwingerde@xxxxxxxxx> wrote:
> On 11/21/09 02:30, David Ellingsworth wrote:
>> Wasn't sure where to send this, but with the latest 2.6.32-rc8-wl
>> kernel built from the wireless-testing repository I'm getting a number
>> of "ieee80211_tx_status: headroom too small" errors in my syslog. I'm
>> using the rt61pci driver in conjunction with hostap as a wpa2 secured
>> access point. The relevant information about my card from lspci is:
>>
>> 01:08.0 0280: 1814:0301
>>         Subsystem: 1458:e934
>>         Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop-
>> ParErr- Stepping- SERR+ FastB2B- DisINTx-
>>         Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=slow >TAbort-
>> <TAbort- <MAbort- >SERR- <PERR- INTx-
>>         Latency: 64, Cache Line Size: 128 bytes
>>         Interrupt: pin A routed to IRQ 18
>>         Region 0: Memory at fe6f0000 (32-bit, non-prefetchable) [size=32K]
>>         Capabilities: [40] Power Management version 2
>>                 Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA
>> PME(D0-,D1-,D2-,D3hot-,D3cold-)
>>                 Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
>>         Kernel driver in use: rt61pci
>>
>> If you need any other information, I'll be happy to provide it.
>>
>
> Hi David,
>
> This seems to be caused by the rt2x00 driver not properly declaring its alignment
> maneuvring space properly, and thus it doesn't leave enough headroom left for
> copying to the monitor interface.
>
> Can you check whether the attached patch fixes the issue for you?
> Note: patch looks a bit bigger than it actually is due to indenting cleanups.
>

Gertjan,

I haven't really been able to test this. The kernel version I was
using at the time was 2.6.32-rc7-wl and not 2.6.32-rc8-wl. I'm rather
certain the patch will resolve the issue, but I've been unable to get
my wireless card to function properly with the latest 2.6.32-rc8-wl
master branch. I'm not entirely sure what changed since two days ago,
but I know the following:

1. 2.6.32-rc8 from Linus' master branch works fine but still exhibits
this issue. However, this patch will not apply on top of 2.6.32-rc8.

2. 2.6.32-rc7-wl(11/19/2009) worked fine with the exception of the
above mentioned error. Unable to test patch since I pulled all the
recent modifications down.
3. 2.6.32-rc8-wl does not work at all for me, but patch does apply.

I'm not entirely sure what the differences are between Linus' master
branch of 2.6.32-rc8 and the current 2.6.32-rc8-wl tree are or what
changes have been made on the wireless-testing master branch in the
last couple of days that are preventing me from fully testing this
patch.

With the current wireless-testing master branch, 2.6.32-rc8-wl, with
and without the patch I can associate and authenticate with my AP but
am unable to do anything else. Any attempt to establish a wireless
connection thus dies while trying to obtain an ip address via DHCP.
Sadly, no errors are logged indicating what the cause of this problem
might be. Given that I've only seen these errors after establishing a
wireless connection, it's a little difficult for me to test without
being able to transmit any data.

I don't know if it's worth the effort or not, but if this patch were
re-based against Linus' master branch I might be able to test it since
my AP at least works with 2.6.32-rc8.

Regards,

David Ellingsworth
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