On Sun, Nov 22, 2009 at 2:51 PM, Gertjan van Wingerde <gertjan@xxxxxxxxxxxxxxx> wrote: > On 11/22/09 19:48, Gertjan van Wingerde wrote: >> On 11/22/09 18:59, David Ellingsworth wrote: >>> On Sun, Nov 22, 2009 at 7:47 AM, Gertjan van Wingerde >>> <gwingerde@xxxxxxxxx> wrote: >>>> On 11/22/09 08:09, David Ellingsworth wrote: >>>>> 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. >>>> >>>> David, >>>> >>>> OK. Find attached the patch ported to Linus' tree. It should apply to >>>> any version of Linus' tree after 2.6.32-rc8. >>>> I think it is good to get real confirmation that the patch behaves >>>> as expected. >>>> >>>> --- >>>> Gertjan. >>>> >>> >>> Gertjan, >>> >>> The patch applies but doesn't quite fix the issue with the rt61pci >>> driver. With the patch applied, I still occasionally receive the error >>> message. I added a printk after the error to see how much was missing. >>> It indicates that skb_headroom is 12 and sizeof(*rthdr) is 13 when it >>> fails. >>> >> >> David, >> >> That is unexpected. This more starts to look like a problem that is >> outside of rt2x00. >> >> Would you be able to see what the available skb_headroom is when the TX >> frame enters the rt61pci driver, i.e. when the rt2x00mac_tx function is >> entered? >> > > (cc-ing Johannes, as this seems to be pointing towards mac80211 as well) > > David, > > I think I got figured out why the patch I sent didn't work. It seems mac80211 > doesn't reserve headroom for both the driver requested space and the special > monitor interface header at the same time, but just for the maximum of the two. > This seems to be because it assumes that they are not needed at the same time. > However, this is not true for rt2x00, as it uses the headroom to align the frame > and never reclaims the used headroom (as the whole frame was moved forward in the > skb). > > The easy fix here is to let mac80211 reserve headroom for both numbers, instead of > just the maximum. > > Find the patch to achieve that attached. > > I think that with both the rt2x00 patch and this patch applied the problem should > be gone. > > --- > Gertjan. > Gertjan, >From what I can tell, the combination of both of these patches seems to correct the issue. I have not experienced the error after applying the patch to mac80211. Thanks for the help. Regards, David Ellingsworth -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
