Hi Aniroop,
On Tue, Dec 16, 2014 at 10:26:34PM +0530, Aniroop Mathur wrote:
> This patch adds support for CLOCK_BOOTTIME for input event timestamp.
> CLOCK_BOOTTIME includes suspend time, so it would allow aplications
> to get correct time difference between two events even when system
> resumes from suspend state.
>
> Signed-off-by: Aniroop Mathur <a.mathur@xxxxxxxxxxx>
> ---
> drivers/input/evdev.c | 33 +++++++++++++++++++++------------
> 1 file changed, 21 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
> index de05545..7825794 100644
> --- a/drivers/input/evdev.c
> +++ b/drivers/input/evdev.c
> @@ -28,6 +28,13 @@
> #include <linux/cdev.h>
> #include "input-compat.h"
>
> +enum clock_type {
> + REAL = 0,
> + MONO,
> + BOOT,
> + CLK_MAX
> +};
> +
> struct evdev {
> int open;
> struct input_handle handle;
> @@ -108,8 +115,9 @@ static void evdev_queue_syn_dropped(struct evdev_client *client)
> struct input_event ev;
> ktime_t time;
>
> - time = (client->clkid == CLOCK_MONOTONIC) ?
> - ktime_get() : ktime_get_real();
> + time = (client->clkid == CLOCK_REALTIME) ?
> + ktime_get_real() : (client->clkid == CLOCK_MONOTONIC) ?
> + ktime_get() : ktime_get_boottime();
>
> ev.time = ktime_to_timeval(time);
> ev.type = EV_SYN;
> @@ -159,7 +167,7 @@ static void __pass_event(struct evdev_client *client,
>
> static void evdev_pass_values(struct evdev_client *client,
> const struct input_value *vals, unsigned int count,
> - ktime_t mono, ktime_t real)
> + ktime_t *ev_time)
> {
> struct evdev *evdev = client->evdev;
> const struct input_value *v;
> @@ -169,8 +177,9 @@ static void evdev_pass_values(struct evdev_client *client,
> if (client->revoked)
> return;
>
> - event.time = ktime_to_timeval(client->clkid == CLOCK_MONOTONIC ?
> - mono : real);
> + event.time = ktime_to_timeval(client->clkid == CLOCK_REALTIME ?
> + ev_time[REAL] : client->clkid == CLOCK_MONOTONIC ?
> + ev_time[MONO] : ev_time[BOOT]);
This becomes unwieldy. Should we have client->clk_type instead of
client->clkid and convert CLOCK_* into your EVDEV_CLK_{REAL|MONO|BOOT}
when setting it in ioctl and then do
event.time = ktime_to_timeval(ev_time[client->clk_offset]);
>
> /* Interrupts are disabled, just acquire the lock. */
> spin_lock(&client->buffer_lock);
> @@ -198,21 +207,21 @@ static void evdev_events(struct input_handle *handle,
> {
> struct evdev *evdev = handle->private;
> struct evdev_client *client;
> - ktime_t time_mono, time_real;
> + ktime_t ev_time[CLK_MAX];
>
> - time_mono = ktime_get();
> - time_real = ktime_mono_to_real(time_mono);
> + ev_time[MONO] = ktime_get();
> + ev_time[REAL] = ktime_mono_to_real(ev_time[MONO]);
> + ev_time[BOOT] = ktime_get_boottime();
I do not think we want to use ktime_get_boottime() here; I'd rather you
use ktime_mono_to_anY(ev_time[MONO], TK_OFFS_BOOT) so that all 3 times
are consistent.
>
> rcu_read_lock();
>
> client = rcu_dereference(evdev->grab);
>
> if (client)
> - evdev_pass_values(client, vals, count, time_mono, time_real);
> + evdev_pass_values(client, vals, count, ev_time);
> else
> list_for_each_entry_rcu(client, &evdev->client_list, node)
> - evdev_pass_values(client, vals, count,
> - time_mono, time_real);
> + evdev_pass_values(client, vals, count, ev_time);
>
> rcu_read_unlock();
> }
> @@ -874,7 +883,7 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
> case EVIOCSCLOCKID:
> if (copy_from_user(&i, p, sizeof(unsigned int)))
> return -EFAULT;
> - if (i != CLOCK_MONOTONIC && i != CLOCK_REALTIME)
> + if (i != CLOCK_MONOTONIC && i != CLOCK_REALTIME && i != CLOCK_BOOTTIME)
> return -EINVAL;
> client->clkid = i;
> return 0;
> --
> 1.9.1
>
Thanks.
--
Dmitry
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