Comment 40 for bug 1415880

Okay, so after reading all the bug I have the following summary:

"""
1. The current trusty repository bcmwl-kernel-source 6.30.223.141+bdcom-0ubuntu2 is used on my wife's laptop. This system is not experiencing null pointer crashes OR Scan_results errors. This evidence strongly suggests both problems were introduced with 6.30.223.248+bdcom-0ubuntu1.
"""

We have a problem introduced in between:

bcmwl-kernel-source | 6.30.223.141+bdcom-0ubuntu2

and

bcmwl-kernel-source | 6.30.223.248+bdcom-0ubuntu0.1
bcmwl-kernel-source | 6.30.223.248+bdcom-0ubuntu2
bcmwl-kernel-source | 6.30.223.248+bdcom-0ubuntu4

"""
2. On checking syslog carefully, the Scan_results errors are often associated with the system running slowly and "[TTM] Out of kernel memory" messages being logged.

https://bugs.launchpad.net/ubuntu/+source/bcmwl/+bug/1415880/comments/15

I'm now on vivid (via do-release-upgrade -d), The problem reappears without the patch. I am now reapplying the patch and see if it works out. On vivid, with the patch, I still get the warning, but the connection doesn't drop (at least for now, fingers crossed).

this patch fixes kernel crashes with kernels >=3.18 for me on BCM43228.
I'm currently using it on top of vivids bcmwl-kernel-source: 6.30.223.248+bdcom-0ubuntu2 and the vivid 3.19.0 kernel
"""

It looks like the patch fixes the out of memory problem.

"""
-kernel 3.18.9-031809-generic.
-patch applied.

Much better now. However, crashes still occur:e.g.
-sudo rmmod wl cfg80211
-sudo modprobe wl > results in a crash.

workaround:
-sudo modprobe cfg80211
wait for abount 10 seconds
-sudo modprobe wl
"""

But still there is a minor problem with "suspension".

"""
Just to add confirmation that I was seeing the kernel panics on a Dell XPS 13 Developer Edition after upgrading to 15.04 (BIOS A04), and after applying Jesse/PierreF's patch, suspend/resume is now working fine.

The patch from #27 appears to have fixed the kernel panics on suspend for me as well on my Dell XPS 13 Developer Edition (2015 edition) with Ubuntu 15.04 and BIOS A04. Have not seen a panic in five days while before I could not go more than one day without it.
"""

I'll be providing a PPA with the fix and asking for feedback. If the suspend problems still occur we will continue from there. Expect a PPA provided here soon. BTW, I'll provide fixes for Vivid only since Utopic is not supported anymore.

Thank you

Rafael Tinoco
SEG Team