Re: [PATCH] bcma: Fix 'allmodconfig' and BCMA builds on MIPS targets

[James Hogan <jhogan@kernel.org>]

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On Sun, Jan 14, 2018 at 01:34:02PM -0800, Guenter Roeck wrote:
> Mips builds with BCMA host mode enabled fail in mainline and -next
> with:
> 
> In file included from include/linux/bcma/bcma.h:10:0,
>                  from drivers/bcma/bcma_private.h:9,
> 		 from drivers/bcma/main.c:8:
> include/linux/bcma/bcma_driver_pci.h:218:24: error:
> 	field 'pci_controller' has incomplete type
> 
> Bisect points to commit d41e6858ba58c ("MIPS: Kconfig: Set default MIPS
> system type as generic") as the culprit. Analysis shows that the commmit
> changes PCI configuration and enables PCI_DRIVERS_GENERIC. This in turn
> disables PCI_DRIVERS_LEGACY. 'struct pci_controller' is, however, only
> defined if PCI_DRIVERS_LEGACY is enabled.
> 
> Ultimately that means that BCMA_DRIVER_PCI_HOSTMODE depends on
> PCI_DRIVERS_LEGACY. Add the missing dependency.
> 
> Fixes: d41e6858ba58c ("MIPS: Kconfig: Set default MIPS system type as ...")

Well, technically I think commit c5611df96804 ("MIPS: PCI: Introduce
CONFIG_PCI_DRIVERS_LEGACY") is to blame (Cc'ing paul), and the first bad
commit would be commit eed0eabd12ef ("MIPS: generic: Introduce generic
DT-based board support") which selects PCI_DRIVERS_GENERIC and is the
only platform to do so. Both commits were first in v4.9-rc1 and I can
reproduce this problem at that latter commit with the appropriate
configuration.

But yes clearly the mentioned commit does also expose that existing
problem more widely and to the default allmodconfig, and it looks like a
reasonable approach for now, so if some mention of the other two commits
is added:

Reviewed-by: James Hogan <jhogan@kernel.org>

Having it in 4.15 would be great.

Cheers
James

> Cc: Matt Redfearn <matt.redfearn@imgtec.com>
> Cc: James Hogan <jhogan@kernel.org>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> I am aware that this problem has been reported several times. I have
> not been able to find a fix, but I may have missed it. If so, my
> apologies for the noise.
> 
> Also note that this is not the only fix required; commit d41e6858ba58c,
> as simple as it looks like, does a pretty good job messing up
> "mips:allmodconfig" builds.
> 
>  drivers/bcma/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/bcma/Kconfig b/drivers/bcma/Kconfig
> index 02d78f6cecbb..ba8acca036df 100644
> --- a/drivers/bcma/Kconfig
> +++ b/drivers/bcma/Kconfig
> @@ -55,7 +55,7 @@ config BCMA_DRIVER_PCI
>  
>  config BCMA_DRIVER_PCI_HOSTMODE
>  	bool "Driver for PCI core working in hostmode"
> -	depends on MIPS && BCMA_DRIVER_PCI
> +	depends on MIPS && BCMA_DRIVER_PCI && PCI_DRIVERS_LEGACY
>  	help
>  	  PCI core hostmode operation (external PCI bus).
>  
> -- 
> 2.7.4
> 

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