diff options
Diffstat (limited to 'drivers/input/gameport/gameport.c')
| -rw-r--r-- | drivers/input/gameport/gameport.c | 41 |
1 files changed, 40 insertions, 1 deletions
diff --git a/drivers/input/gameport/gameport.c b/drivers/input/gameport/gameport.c index 24c41ba7d4e0..e29c04e2aff4 100644 --- a/drivers/input/gameport/gameport.c +++ b/drivers/input/gameport/gameport.c @@ -23,6 +23,7 @@ #include <linux/workqueue.h> #include <linux/sched.h> /* HZ */ #include <linux/mutex.h> +#include <linux/timekeeping.h> /*#include <asm/io.h>*/ @@ -30,6 +31,10 @@ MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); MODULE_DESCRIPTION("Generic gameport layer"); MODULE_LICENSE("GPL"); +static bool use_ktime = true; +module_param(use_ktime, bool, 0400); +MODULE_PARM_DESC(use_ktime, "Use ktime for measuring I/O speed"); + /* * gameport_mutex protects entire gameport subsystem and is taken * every time gameport port or driver registrered or unregistered. @@ -76,6 +81,38 @@ static unsigned int get_time_pit(void) static int gameport_measure_speed(struct gameport *gameport) { + unsigned int i, t, tx; + u64 t1, t2, t3; + unsigned long flags; + + if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW)) + return 0; + + tx = ~0; + + for (i = 0; i < 50; i++) { + local_irq_save(flags); + t1 = ktime_get_ns(); + for (t = 0; t < 50; t++) + gameport_read(gameport); + t2 = ktime_get_ns(); + t3 = ktime_get_ns(); + local_irq_restore(flags); + udelay(i * 10); + t = (t2 - t1) - (t3 - t2); + if (t < tx) + tx = t; + } + + gameport_close(gameport); + t = 1000000 * 50; + if (tx) + t /= tx; + return t; +} + +static int old_gameport_measure_speed(struct gameport *gameport) +{ #if defined(__i386__) unsigned int i, t, t1, t2, t3, tx; @@ -521,7 +558,9 @@ static void gameport_add_port(struct gameport *gameport) if (gameport->parent) gameport->parent->child = gameport; - gameport->speed = gameport_measure_speed(gameport); + gameport->speed = use_ktime ? + gameport_measure_speed(gameport) : + old_gameport_measure_speed(gameport); list_add_tail(&gameport->node, &gameport_list); |