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Date:   Mon, 30 Oct 2017 15:14:54 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Hans Verkuil <hans.verkuil@...co.com>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-media@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] media: av7110: switch to useing timer_setup()

On Tue, Oct 24, 2017 at 5:40 PM, Dmitry Torokhov
<dmitry.torokhov@...il.com> wrote:
> In preparation for unconditionally passing the struct timer_list pointer to
> all timer callbacks, switch to using the new timer_setup() and from_timer()
> to pass the timer pointer explicitly.
>
> Also stop poking into input core internals and override its autorepeat
> timer function. I am not sure why we have such convoluted autorepeat
> handling in this driver instead of letting input core handle autorepeat,
> but this preserves current behavior of allowing controlling autorepeat
> delay and forcing autorepeat period to be whatever the hardware has.
>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>

Reviewed-by: Kees Cook <keescook@...omium.org>
(with the Subject typo fixed)

Hans, since this depends on the input side not changing first, I think
it makes sense for Dmitry to carry this in the Input tree before the
Input timer updates. Would that be okay?

Thanks!

-Kees

> ---
>
> Note that this has not been tested on the hardware. But it should
> compile, so I have that going for me.
>
>  drivers/media/pci/ttpci/av7110.h    |  4 ++--
>  drivers/media/pci/ttpci/av7110_ir.c | 40 +++++++++++++++++--------------------
>  2 files changed, 20 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/media/pci/ttpci/av7110.h b/drivers/media/pci/ttpci/av7110.h
> index 347827925c14..0aa3c6f01853 100644
> --- a/drivers/media/pci/ttpci/av7110.h
> +++ b/drivers/media/pci/ttpci/av7110.h
> @@ -80,10 +80,11 @@ struct av7110;
>
>  /* infrared remote control */
>  struct infrared {
> -       u16     key_map[256];
> +       u16                     key_map[256];
>         struct input_dev        *input_dev;
>         char                    input_phys[32];
>         struct timer_list       keyup_timer;
> +       unsigned long           keydown_time;
>         struct tasklet_struct   ir_tasklet;
>         void                    (*ir_handler)(struct av7110 *av7110, u32 ircom);
>         u32                     ir_command;
> @@ -93,7 +94,6 @@ struct infrared {
>         u8                      inversion;
>         u16                     last_key;
>         u16                     last_toggle;
> -       u8                      delay_timer_finished;
>  };
>
>
> diff --git a/drivers/media/pci/ttpci/av7110_ir.c b/drivers/media/pci/ttpci/av7110_ir.c
> index ca05198de2c2..b602e64b3412 100644
> --- a/drivers/media/pci/ttpci/av7110_ir.c
> +++ b/drivers/media/pci/ttpci/av7110_ir.c
> @@ -84,9 +84,9 @@ static u16 default_key_map [256] = {
>
>
>  /* key-up timer */
> -static void av7110_emit_keyup(unsigned long parm)
> +static void av7110_emit_keyup(struct timer_list *t)
>  {
> -       struct infrared *ir = (struct infrared *) parm;
> +       struct infrared *ir = from_timer(ir, keyup_timer, t);
>
>         if (!ir || !test_bit(ir->last_key, ir->input_dev->key))
>                 return;
> @@ -152,19 +152,20 @@ static void av7110_emit_key(unsigned long parm)
>                 return;
>         }
>
> -       if (timer_pending(&ir->keyup_timer)) {
> -               del_timer(&ir->keyup_timer);
> +       if (del_timer(&ir->keyup_timer)) {
>                 if (ir->last_key != keycode || toggle != ir->last_toggle) {
> -                       ir->delay_timer_finished = 0;
> +                       ir->keydown_time = jiffies;
>                         input_event(ir->input_dev, EV_KEY, ir->last_key, 0);
>                         input_event(ir->input_dev, EV_KEY, keycode, 1);
>                         input_sync(ir->input_dev);
> -               } else if (ir->delay_timer_finished) {
> +               } else if (time_after(jiffies, ir->keydown_time +
> +                               msecs_to_jiffies(
> +                                       ir->input_dev->rep[REP_PERIOD]))) {
>                         input_event(ir->input_dev, EV_KEY, keycode, 2);
>                         input_sync(ir->input_dev);
>                 }
>         } else {
> -               ir->delay_timer_finished = 0;
> +               ir->keydown_time = jiffies;
>                 input_event(ir->input_dev, EV_KEY, keycode, 1);
>                 input_sync(ir->input_dev);
>         }
> @@ -172,9 +173,7 @@ static void av7110_emit_key(unsigned long parm)
>         ir->last_key = keycode;
>         ir->last_toggle = toggle;
>
> -       ir->keyup_timer.expires = jiffies + UP_TIMEOUT;
> -       add_timer(&ir->keyup_timer);
> -
> +       mod_timer(&ir->keyup_timer, jiffies + UP_TIMEOUT);
>  }
>
>
> @@ -184,12 +183,19 @@ static void input_register_keys(struct infrared *ir)
>         int i;
>
>         set_bit(EV_KEY, ir->input_dev->evbit);
> -       set_bit(EV_REP, ir->input_dev->evbit);
>         set_bit(EV_MSC, ir->input_dev->evbit);
>
>         set_bit(MSC_RAW, ir->input_dev->mscbit);
>         set_bit(MSC_SCAN, ir->input_dev->mscbit);
>
> +       set_bit(EV_REP, ir->input_dev->evbit);
> +       /*
> +        * By setting the delay before registering input device we
> +        * indicate that we will be implementing the autorepeat
> +        * ourselves.
> +        */
> +       ir->input_dev->rep[REP_DELAY] = 250;
> +
>         memset(ir->input_dev->keybit, 0, sizeof(ir->input_dev->keybit));
>
>         for (i = 0; i < ARRAY_SIZE(ir->key_map); i++) {
> @@ -205,15 +211,6 @@ static void input_register_keys(struct infrared *ir)
>  }
>
>
> -/* called by the input driver after rep[REP_DELAY] ms */
> -static void input_repeat_key(unsigned long parm)
> -{
> -       struct infrared *ir = (struct infrared *) parm;
> -
> -       ir->delay_timer_finished = 1;
> -}
> -
> -
>  /* check for configuration changes */
>  int av7110_check_ir_config(struct av7110 *av7110, int force)
>  {
> @@ -333,8 +330,7 @@ int av7110_ir_init(struct av7110 *av7110)
>         av_list[av_cnt++] = av7110;
>         av7110_check_ir_config(av7110, true);
>
> -       setup_timer(&av7110->ir.keyup_timer, av7110_emit_keyup,
> -                   (unsigned long)&av7110->ir);
> +       timer_setup(&av7110->ir.keyup_timer, av7110_emit_keyup, 0);
>
>         input_dev = input_allocate_device();
>         if (!input_dev)
> --
> 2.15.0.rc0.271.g36b669edcc-goog
>
>
> --
> Dmitry



-- 
Kees Cook
Pixel Security

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