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Subject[PATCH] drivers/idle: make intel_idle.c driver more explicitly non-modular
Date
The Kconfig for this driver is currently declared with:

config INTEL_IDLE
bool "Cpuidle Driver for Intel Processors"

...meaning that it currently is not being built as a module by anyone.

This was done in commit 6ce9cd8669fa1195fdc21643370e34523c7ac988
("intel_idle: disable module support") since "...the module capability
is cauing more trouble than it is worth."

Since this was done over 5y ago, it is safe to say there is no big desire
to overcome the issues with modular versions. So lets remove the modular
code that is essentially orphaned, so that when reading the driver there
is no doubt it is builtin-only.

Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit. At a
later date we might want to consider whether subsys_init or another
init category seems more appropriate than device_init.

We replace module.h with moduleparam.h since the file does declare
some module parameters, and leaving them as such is currently the
easiest way to remain compatible with existing boot arg use cases.

Note that MODULE_DEVICE_TABLE is a no-op for non-modular code.

Also note that we can't remove intel_idle_cpuidle_devices_uninit() as
that is still used for unwind purposes if the init fails.

We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.

Cc: Len Brown <lenb@kernel.org>
Cc: Len Brown <len.brown@intel.com>
Cc: linux-pm@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
drivers/idle/intel_idle.c | 35 ++++++++---------------------------
1 file changed, 8 insertions(+), 27 deletions(-)

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index ba947df5a8c7..d1b5a821664d 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -46,8 +46,6 @@
* to avoid complications with the lapic timer workaround.
* Have not seen issues with suspend, but may need same workaround here.
*
- * There is currently no kernel-based automatic probing/loading mechanism
- * if the driver is built as a module.
*/

/* un-comment DEBUG to enable pr_debug() statements */
@@ -60,7 +58,7 @@
#include <linux/sched.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
-#include <linux/module.h>
+#include <linux/moduleparam.h>
#include <asm/cpu_device_id.h>
#include <asm/mwait.h>
#include <asm/msr.h>
@@ -948,7 +946,6 @@ static const struct x86_cpu_id intel_idle_ids[] __initconst = {
ICPU(0x57, idle_cpu_knl),
{}
};
-MODULE_DEVICE_TABLE(x86cpu, intel_idle_ids);

/*
* intel_idle_probe()
@@ -1247,28 +1244,12 @@ static int __init intel_idle_init(void)

return 0;
}
+device_initcall(intel_idle_init);

-static void __exit intel_idle_exit(void)
-{
- intel_idle_cpuidle_devices_uninit();
- cpuidle_unregister_driver(&intel_idle_driver);
-
- cpu_notifier_register_begin();
-
- if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
- on_each_cpu(__setup_broadcast_timer, (void *)false, 1);
- __unregister_cpu_notifier(&cpu_hotplug_notifier);
-
- cpu_notifier_register_done();
-
- return;
-}
-
-module_init(intel_idle_init);
-module_exit(intel_idle_exit);
-
+/*
+ * We are not really modular, but we used to support that. Meaning we also
+ * support "intel_idle.max_cstate=..." at boot and also a read-only export of
+ * it at /sys/module/intel_idle/parameters/max_cstate -- so using module_param
+ * is the easiest way (currently) to continue doing that.
+ */
module_param(max_cstate, int, 0444);
-
-MODULE_AUTHOR("Len Brown <len.brown@intel.com>");
-MODULE_DESCRIPTION("Cpuidle driver for Intel Hardware v" INTEL_IDLE_VERSION);
-MODULE_LICENSE("GPL");
--
2.6.1
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