Re: Regression caused by commit 882164a4a928

[Michael BÃsch]

On Wed, 9 May 2018 13:55:43 +0100
Matt Redfearn <matt.redfearn@xxxxxxxx> wrote:

> Hi Larry
> 
> On 07/05/18 16:44, Larry Finger wrote:
> > Matt,
> > 
> > Although commit 882164a4a928 ("ssb: Prevent build of PCI host features 
> > in module") appeared to be harmless, it leads to complete failure of 
> > drivers b43. and b43legacy, and likely affects b44 as well. The problem 
> > is that CONFIG_SSB_PCIHOST is undefined, which prevents the compilation 
> > of the code that controls the PCI cores of the device. See 
> > https://bugzilla.redhat.com/show_bug.cgi?id=1572349 for details.  
> 
> Sorry for the breakage :-/
> 
> > 
> > As the underlying errors ("pcibios_enable_device" undefined, and 
> > "register_pci_controller" undefined) do not appear on the architectures 
> > that I have tested (x86_64, x86, and ppc), I suspect something in the 
> > arch-specific code for your setup (MIPS?). As I have no idea on how to 
> > fix that problem, would the following patch work for you?
> > 
> > diff --git a/drivers/ssb/Kconfig b/drivers/ssb/Kconfig
> > index 9371651d8017..3743533c8057 100644
> > --- a/drivers/ssb/Kconfig
> > +++ b/drivers/ssb/Kconfig
> > @@ -117,7 +117,7 @@ config SSB_SERIAL
> > 
> >  Âconfig SSB_DRIVER_PCICORE_POSSIBLE
> >  ÂÂÂÂÂÂÂ bool
> > -ÂÂÂÂÂÂ depends on SSB_PCIHOST && SSB = y
> > +ÂÂÂÂÂÂ depends on SSB_PCIHOST && (SSB = y || !MIPS)
> >  ÂÂÂÂÂÂÂ default y
> > 
> >  Âconfig SSB_DRIVER_PCICORE  
> 
> I believe that the problem stems from these drivers being used for some 
> wireless AP functionality built into some MIPS based SoCs. The Kconfig 
> rules sort out building this additional functionality when configured 
> for MIPS (in a round about sort of way), but it allowed it even when SSB 
> is a module, leading to build failures. My patch was intended to prevent 
> that.
> 
> There was a similar issue in the same Kconfig file, introduced by 
> c5611df96804 and fixed by a9e6d44ddecc. It was fixed the same way as you 
> suggest. I've tested the above patch and it does work for MIPS 
> (preventing the PCICORE being built into the module).
> 
> Tested-by: Matt Redfearn <matt.redfearn@xxxxxxxx>


Could you please try this?

config SSB_DRIVER_PCICORE_POSSIBLE
	depends on SSB_PCIHOST

config SSB_PCICORE_HOSTMODE
	depends on SSB_DRIVER_PCICORE && SSB_DRIVER_MIPS && (SSB = y) && PCI_DRIVERS_LEGACY


The affected API pcibios_enable_device() and register_pci_controller()
is only used in HOSTMODE. So I think it makes sense to make HOSTMODE
depend on SSB=y and PCI_DRIVERS_LEGACY.

PCICore itself does not use the API, if hostmode is disabled.

-- 
Michael

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