Hello Mr. Torokhov,
On Thu, Dec 18, 2014 at 3:33 AM, Dmitry Torokhov
<dmitry.torokhov@xxxxxxxxx> wrote:
> On Thu, Dec 18, 2014 at 03:03:26AM +0530, Aniroop Mathur wrote:
>> Hello Mr. Torokhov,
>>
>> On Wed, Dec 17, 2014 at 11:50 PM, Dmitry Torokhov
>> <dmitry.torokhov@xxxxxxxxx> wrote:
>> > 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();
>> >>
>>
>> Is this okay ?
>> To improve readabilty,
>> how about adding a new funtion to get time depending upon clkid like below ?
>> time = get_clk_time(client->clkid);
>>
>> static ktime_t get_clk_time(int id)
>> {
>> switch (id) {
>>
>> case CLOCK_REALTIME: return ktime_get_real();
>> case CLOCK_MONOTONIC: return ktime_get();
>> case CLOCK_BOOTTIME: return ktime_get_bootime();
>> }
>> }
>
> Just open-code it in evdev_queue_syn_dropped() since there is only place
> where we call it. And use clk_type instead of clock id-.
>
>>
>> >> 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]);
>> >
>>
>> Sure, using clk_type would be better and improve code readability.
>>
>> I am afraid how converting CLOCK_* into your
>> EVDEV_CLK_{REAL|MONO|BOOT} will help
>> because we cannot have ev_time array size more than CLK_MAX (3).
>>
>> Did you mean to have following changes:
>>
>> 1. Add clk_type variable
>> struct evdev_client {
>> int clkid:
>> + int clk_type;
>> }
>
> I meant replacing clkid with clk_type in evdev_client.
>
>>
>> 2. Add new funtion for setting clk_type to improve readability
>> static int set_clk_type(struct evdev_client *client, int id)
>
>
> evdev_set_clk_type() to keep with the style.
>
>> {
>> switch (id) {
>>
>> case CLOCK_REALTIME: client->clk_type = EV_REAL; break;
>> case CLOCK_MONOTONIC: client->clk_type = EV_MONO; break;
>> case CLOCK_BOOTTIME: client->clk_type = EV_BOOT; break;
>> default: return -1
>
> -EINVAL here, otherwise yes.
>
>> }
>>
>> return 0;
>> }
>>
>> 3. Addition in ioctl call
>> case EVIOCSCLOCKID:
>> ...
>> if (!set_clk_type())
>> return -EINVAL;
>>
>
> error = evdev_set_clktype(i);
> if (error)
> return error;
>
>> client->clkid = i;
>
> Drop this.
>
>> return 0;
>>
>> 4. Change in evdev_pass_values function
>> event.time = ktime_to_timeval(ev_time[client->clk_type]);
>
> Yes.
>
>>
>> >>
>> >> /* 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.
>> >
>>
>> Sure. I will send the updated patch with this change.
>>
>> >>
>> >> 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
>>
>> Thanks,
>> Aniroop Mathur
>
> --
> Dmitry
Thanks for the suggestions !!
I have sent you the updated patch with new changes done.
Thanks,
Aniroop
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