Regression: bcm4312 lp-phy device not working in 4.17-rc5 kernel

[Chris Vine <vine35792468@gmail.com>]

On Mon, 14 May 2018 20:02:05 +0200
Michael B?sch <m@bues.ch> wrote:
> On Mon, 14 May 2018 19:55:39 +0200
> Michael B?sch <m@bues.ch> wrote:
> 
> > On Mon, 14 May 2018 18:49:53 +0100
> > Chris Vine <vine35792468@gmail.com> wrote:
> > 
> > > I have an old netbook with a Broadcom bcm4312 802.11b/g lp-phy
> > > [14e4:4315] (rev 01) wifi device.  This works up to and including the
> > > 4.16 kernel, but not with 4.17-rc5.
> > > 
> > > The b43, mac80211, cfg80211, ssb and mmc_core modules are loaded OK, as
> > > is the firmware, and the wlan0 interface will come up, but any attempt
> > > to use the interface fails and it cannot (for example) scan.
> > > 
> > > No useful error messages are given.  The interface (wlan0) is just
> > > reported as not being ready.  
> > 
> > Hi,
> > 
> > thanks for your report.
> > 
> > Can you please provide all kernel log messages anyway?
> > And what does "not ready" mean exactly?
> > 
> > It would be extremely helpful if you'd do a git bisect to find the
> > commit that broke it.
> > 
> 
> Ok, I just noticed that mainline still contains the ssb breakage.
> 
> So you are most likely hitting this:
> https://patchwork.kernel.org/patch/10393729/

Yes thanks, applying that patch resolves the issue fine.  There was a
similar problem with disabled PCI support for b43 which found its way
into the 4.15.0/4.15.1 kernels:
https://git.kernel.org/pub/scm/linux/kernel/git/kvalo/wireless-drivers.git/commit/?id=a9e6d44ddeccd3522670e641f1ed9b068e746ff7
At least this bug should avoid getting into the mainline release.

Chris