ipmi: Turn off default probing of interfaces

The default probing can cause problems with some system, slow booting,
extra CPU usages, etc.  Turn it off by default and give a config option
to enable it.

From: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 13 insertions, 1 deletions

diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
index 0baa8fab4ea7..db1c9b7adaa6 100644
--- a/drivers/char/ipmi/Kconfig
+++ b/drivers/char/ipmi/Kconfig
@@ -50,6 +50,18 @@ config IPMI_SI
          Currently, only KCS and SMIC are supported.  If
          you are using IPMI, you should probably say "y" here.
 
+config IPMI_SI_PROBE_DEFAULTS
+       bool 'Probe for all possible IPMI system interfaces by default'
+       default n
+       depends on IPMI_SI
+       help
+         Modern systems will usually expose IPMI interfaces via a discoverable
+         firmware mechanism such as ACPI or DMI. Older systems do not, and so
+         the driver is forced to probe hardware manually. This may cause boot
+         delays. Say "n" here to disable this manual probing. IPMI will then
+         only be available on older systems if the "ipmi_si_intf.trydefaults=1"
+         boot argument is passed.
+
 config IPMI_WATCHDOG
        tristate 'IPMI Watchdog Timer'
        help
diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index 9c4069151955..25a1436a4291 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -1239,7 +1239,7 @@ static bool          si_tryplatform = 1;
 #ifdef CONFIG_PCI
 static bool          si_trypci = 1;
 #endif
-static bool          si_trydefaults = 1;
+static bool          si_trydefaults = IS_ENABLED(CONFIG_IPMI_SI_PROBE_DEFAULTS);
 static char          *si_type[SI_MAX_PARMS];
 #define MAX_SI_TYPE_STR 30
 static char          si_type_str[MAX_SI_TYPE_STR];