Re: [PATCH V2] Change ACPI IPMI support to "default y"

[Russ Anderson]

On Tue, Feb 18, 2014 at 11:28:29AM -0500, Matthew Garrett wrote:
> The ACPI IPMI driver implements IPMI operation region support for the ACPI
> core. Systems that declare ACPI operation regions may reference them at any
> time, including during kernel initialisation. These accesses will fail
> unless the ACPI IPMI driver is present, and undesirable system behaviour
> may result. Set the default to Y in order to encourage distributions and
> users to configure kernels to avoid awkward surprises.

No, please do not build the ipmi_si driver into the kernel.
Not all systems want, or need, the ipmi_si driver.  

The distro that added this change created all sorts of support
problems.  Problems include kipmi0 spinning at 100% of cpu
(creating a performance hit) and long boot delays (as the
kernel tries to talk to a BMC that will never respond).
It has been a big mess.

Nacked-by: Russ Anderson <rja@xxxxxxx>


> Signed-off-by: Matthew Garrett <matthew.garrett@xxxxxxxxxx>
> ---
> Actually, I guess we also want this on CONFIG_IPMI_HANDLER for least
> surprise
> 
>  drivers/acpi/Kconfig      | 2 +-
>  drivers/char/ipmi/Kconfig | 2 ++
>  2 files changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index 4770de5..0e6aab9 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -162,7 +162,7 @@ config ACPI_PROCESSOR
>  config ACPI_IPMI
>  	tristate "IPMI"
>  	depends on IPMI_SI
> -	default n
> +	default y
>  	help
>  	  This driver enables the ACPI to access the BMC controller. And it
>  	  uses the IPMI request/response message to communicate with BMC
> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
> index 0baa8fa..eea8464 100644
> --- a/drivers/char/ipmi/Kconfig
> +++ b/drivers/char/ipmi/Kconfig
> @@ -5,6 +5,7 @@
>  menuconfig IPMI_HANDLER
>         tristate 'IPMI top-level message handler'
>         depends on HAS_IOMEM
> +       default y if ACPI
>         help
>           This enables the central IPMI message handler, required for IPMI
>  	 to work.
> @@ -45,6 +46,7 @@ config IPMI_DEVICE_INTERFACE
>  
>  config IPMI_SI
>         tristate 'IPMI System Interface handler'
> +       default y if ACPI
>         help
>           Provides a driver for System Interfaces (KCS, SMIC, BT).
>  	 Currently, only KCS and SMIC are supported.  If
> -- 
> 1.8.5.3
> 
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-- 
Russ Anderson,  Kernel and Performance Software Team Manager
SGI - Silicon Graphics Inc          rja@xxxxxxx
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