On Tue, Nov 29, 2016 at 01:11:31AM +0530, Aniroop Mathur wrote:
> msleep(1~20) may not do what the caller intends, and will often sleep longer.
> (~20 ms actual sleep for any value given in the 1~20ms range)
> This is not the desired behaviour for many cases like device resume time,
> device suspend time, device enable time, connection time, probe time,
> loops, retry logic, etc
> msleep is built on jiffies / legacy timers which are not precise whereas
> usleep_range is build on top of hrtimers so the wakeups are precise.
> Thus, change msleep to usleep_range for precise wakeups.
>
> For example:
> On a machine with tick rate / HZ as 100, msleep(3) will make the process to
> sleep for a minimum period of 10 ms whereas usleep_range(3000, 3100) will make
> sure that the process does not sleep for more than 3100 us or 3.1ms
Again, not needed, if the MAX_TIME sleeps are longer, nobody cares.
>
> Signed-off-by: Aniroop Mathur <a.mathur@xxxxxxxxxxx>
> ---
> drivers/input/joystick/analog.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/input/joystick/analog.c b/drivers/input/joystick/analog.c
> index 3d8ff09..2891704 100644
> --- a/drivers/input/joystick/analog.c
> +++ b/drivers/input/joystick/analog.c
> @@ -88,7 +88,7 @@ MODULE_PARM_DESC(map, "Describes analog joysticks type/capabilities");
> #define ANALOG_EXTENSIONS 0x7ff00
> #define ANALOG_GAMEPAD 0x80000
>
> -#define ANALOG_MAX_TIME 3 /* 3 ms */
> +#define ANALOG_MAX_TIME 3000 /* 3000 us */
> #define ANALOG_LOOP_TIME 2000 /* 2 * loop */
> #define ANALOG_SAITEK_DELAY 200 /* 200 us */
> #define ANALOG_SAITEK_TIME 2000 /* 2000 us */
> @@ -257,7 +257,7 @@ static int analog_cooked_read(struct analog_port *port)
> int i, j;
>
> loopout = (ANALOG_LOOP_TIME * port->loop) / 1000;
> - timeout = ANALOG_MAX_TIME * port->speed;
> + timeout = (ANALOG_MAX_TIME / 1000) * port->speed;
>
> local_irq_save(flags);
> gameport_trigger(gameport);
> @@ -625,20 +625,20 @@ static int analog_init_port(struct gameport *gameport, struct gameport_driver *d
>
> gameport_trigger(gameport);
> t = gameport_read(gameport);
> - msleep(ANALOG_MAX_TIME);
> + usleep_range(ANALOG_MAX_TIME, ANALOG_MAX_TIME + 100);
> port->mask = (gameport_read(gameport) ^ t) & t & 0xf;
> port->fuzz = (port->speed * ANALOG_FUZZ_MAGIC) / port->loop / 1000 + ANALOG_FUZZ_BITS;
>
> for (i = 0; i < ANALOG_INIT_RETRIES; i++) {
> if (!analog_cooked_read(port))
> break;
> - msleep(ANALOG_MAX_TIME);
> + usleep_range(ANALOG_MAX_TIME, ANALOG_MAX_TIME + 100);
> }
>
> u = v = 0;
>
> - msleep(ANALOG_MAX_TIME);
> - t = gameport_time(gameport, ANALOG_MAX_TIME * 1000);
> + usleep_range(ANALOG_MAX_TIME, ANALOG_MAX_TIME + 100);
> + t = gameport_time(gameport, ANALOG_MAX_TIME);
> gameport_trigger(gameport);
> while ((gameport_read(port->gameport) & port->mask) && (u < t))
> u++;
> --
> 2.6.2
>
--
Vojtech Pavlik
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