Bug 74311

Summary:	iwlwifi 7260 fails to connect to AP when 802.11n enabled
Product:	Drivers	Reporter:	Jonathan McDowell (noodles)
Component:	network-wireless	Assignee:	drivers_network-wireless (drivers_network-wireless)
Status:	CLOSED UNREPRODUCIBLE
Severity:	normal	CC:	ilw, kernel
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	3.15-rc1	Subsystem:
Regression:	No	Bisected commit-id:
Attachments:	disable beacon filtering

Description Jonathan McDowell 2014-04-17 17:28:18 UTC

I have a laptop with an Intel 7260 in it that is reliably failing to connect to an 11n AP. If I pass 11n_disable=1 to iwlwifi when loading that module it connects fine. Firmware version is 22.24.8.0. dmesg log with tracing enabled of failing case at:

http://the.earth.li/~noodles/iwlwifi/iwlwifi-fail.log

Device is:

02:00.0 Network controller [0280]: Intel Corporation Wireless 7260 [8086:08b1] (rev 73)
        Subsystem: Intel Corporation Dual Band Wireless-AC 7260 [8086:4470]
        Flags: bus master, fast devsel, latency 0, IRQ 64
        Memory at f7d00000 (64-bit, non-prefetchable) [size=8K]
        Capabilities: [c8] Power Management version 3
        Capabilities: [d0] MSI: Enable+ Count=1/1 Maskable- 64bit+
        Capabilities: [40] Express Endpoint, MSI 00
        Capabilities: [100] Advanced Error Reporting
        Capabilities: [140] Device Serial Number 0c-8b-fd-ff-ff-db-1a-55
        Capabilities: [14c] Latency Tolerance Reporting
        Capabilities: [154] Vendor Specific Information: ID=cafe Rev=1 Len=014 <?>
        Kernel driver in use: iwlwifi

Emmanuel Grumbach requested the output of "sudo trace-cmd record -e iwlwifi -e iwlwifi_msg -e mac80211 -e cfg80211". This is available for the failing case (11n enabled) at:

http://the.earth.li/~noodles/iwlwifi/broken-trace.dat.xz

and in the working case (11n disabled):

http://the.earth.li/~noodles/iwlwifi/working-trace.dat.xz

In both cases the rfkill hardware switch is toggled and Network Manager allowed to try and bring the connection up. In the non working case although the kernel logs the link as being up no DHCP response is ever received. In the working case a response is received and the connection operates without problem,

Comment 1 Emmanuel Grumbach 2014-05-12 16:49:49 UTC

So I finally looked at these, unfortunately, I can't find anything that caught my eye. If you are running 3.15-rcX, can you please try the latest firmware?

https://git.kernel.org/cgit/linux/kernel/git/egrumbach/linux-firmware.git/plain/iwlwifi-7260-9.ucode?id=7a67dbf9c087ef64b3d3fc9ce448c2efdb2e365f

thanks.

Comment 2 Emmanuel Grumbach 2014-05-18 16:11:13 UTC

Created attachment 136621 [details]
disable beacon filtering

This is a fix candidate for 3.13 / 3.14.

Please test - thank you.

Comment 3 Jonathan McDowell 2014-05-19 14:44:46 UTC

No change with the latest firmware and clean 3.15-rc5 - I still need to disable 802.11n to correctly get an IP address. I'll try to get the patch tested in the next couple of days.

Comment 4 Emmanuel Grumbach 2014-05-21 16:27:10 UTC

can you add -dd to your supplicant and send the output?

thanks.

Comment 5 Jonathan McDowell 2014-05-25 23:12:55 UTC

I tried with the beacon filtering patch and saw no difference in behaviour. Unfortunately I now have no access to the problematic network (it was in temporary accomodation while on a work trip). If I see the same issue again then I will get the -dd suplicant output, but at present I'm happily associated to an 11n network served up by a TP Link device.