On Thu, Jun 23, 2011 at 05:13:24PM -0400, Jarod Wilson wrote:
> Due to commit cdda911c34006f1089f3c87b1a1f31ab3a4722f2, evdev only
> becomes readable when the buffer contains an EV_SYN/SYN_REPORT event. If
> we get a repeat or a scancode we don't have a mapping for, we never call
> input_sync, and thus those events don't get reported in a timely
> fashion.
>
> For example, take an mceusb transceiver with a default rc6 keymap. Press
> buttons on an rc5 remote while monitoring with ir-keytable, and you'll
> see nothing. Now press a button on the rc6 remote matching the keymap.
> You'll suddenly get the rc5 key scancodes, the rc6 scancode and the rc6
> key spit out all at the same time.
>
> Pressing and holding a button on a remote we do have a keymap for also
> works rather unreliably right now, due to repeat events also happening
> without a call to input_sync (we bail from ir_do_keydown before getting
> to the point where it calls input_sync).
>
> Easy fix though, just add two strategically placed input_sync calls
> right after our input_event calls for EV_MSC, and all is well again.
> Technically, we probably should have been doing this all along, its just
> that it never caused any functional difference until the referenced
> change went into the input layer.
>
> v2: rework code a bit, per Dmitry's example, so that we only call
> input_sync once per IR signal. There was another hidden bug in the code
> where we were calling input_report_key using last_keycode instead of our
> just discovered keycode, which manifested with the reordering of calling
> input_report_key and setting last_keycode.
>
> Reported-by: Stephan Raue <sraue@xxxxxxxxxxx>
> CC: Stephan Raue <sraue@xxxxxxxxxxx>
> CC: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
> CC: Jeff Brown <jeffbrown@xxxxxxxxxxx>
> CC: Dmitry Torokhov <dtor@xxxxxxx>
> Signed-off-by: Jarod Wilson <jarod@xxxxxxxxxx>
Acked-by: Dmitry Torokhov <dtor@xxxxxxx>
> ---
> drivers/media/rc/rc-main.c | 48 ++++++++++++++++++++++---------------------
> 1 files changed, 25 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c
> index f57cd56..3186ac7 100644
> --- a/drivers/media/rc/rc-main.c
> +++ b/drivers/media/rc/rc-main.c
> @@ -522,18 +522,20 @@ EXPORT_SYMBOL_GPL(rc_g_keycode_from_table);
> /**
> * ir_do_keyup() - internal function to signal the release of a keypress
> * @dev: the struct rc_dev descriptor of the device
> + * @sync: whether or not to call input_sync
> *
> * This function is used internally to release a keypress, it must be
> * called with keylock held.
> */
> -static void ir_do_keyup(struct rc_dev *dev)
> +static void ir_do_keyup(struct rc_dev *dev, bool sync)
> {
> if (!dev->keypressed)
> return;
>
> IR_dprintk(1, "keyup key 0x%04x\n", dev->last_keycode);
> input_report_key(dev->input_dev, dev->last_keycode, 0);
> - input_sync(dev->input_dev);
> + if (sync)
> + input_sync(dev->input_dev);
> dev->keypressed = false;
> }
>
> @@ -549,7 +551,7 @@ void rc_keyup(struct rc_dev *dev)
> unsigned long flags;
>
> spin_lock_irqsave(&dev->keylock, flags);
> - ir_do_keyup(dev);
> + ir_do_keyup(dev, true);
> spin_unlock_irqrestore(&dev->keylock, flags);
> }
> EXPORT_SYMBOL_GPL(rc_keyup);
> @@ -578,7 +580,7 @@ static void ir_timer_keyup(unsigned long cookie)
> */
> spin_lock_irqsave(&dev->keylock, flags);
> if (time_is_before_eq_jiffies(dev->keyup_jiffies))
> - ir_do_keyup(dev);
> + ir_do_keyup(dev, true);
> spin_unlock_irqrestore(&dev->keylock, flags);
> }
>
> @@ -597,6 +599,7 @@ void rc_repeat(struct rc_dev *dev)
> spin_lock_irqsave(&dev->keylock, flags);
>
> input_event(dev->input_dev, EV_MSC, MSC_SCAN, dev->last_scancode);
> + input_sync(dev->input_dev);
>
> if (!dev->keypressed)
> goto out;
> @@ -622,29 +625,28 @@ EXPORT_SYMBOL_GPL(rc_repeat);
> static void ir_do_keydown(struct rc_dev *dev, int scancode,
> u32 keycode, u8 toggle)
> {
> - input_event(dev->input_dev, EV_MSC, MSC_SCAN, scancode);
> -
> - /* Repeat event? */
> - if (dev->keypressed &&
> - dev->last_scancode == scancode &&
> - dev->last_toggle == toggle)
> - return;
> + bool new_event = !dev->keypressed ||
> + dev->last_scancode != scancode ||
> + dev->last_toggle != toggle;
>
> - /* Release old keypress */
> - ir_do_keyup(dev);
> + if (new_event && dev->keypressed)
> + ir_do_keyup(dev, false);
>
> - dev->last_scancode = scancode;
> - dev->last_toggle = toggle;
> - dev->last_keycode = keycode;
> + input_event(dev->input_dev, EV_MSC, MSC_SCAN, scancode);
>
> - if (keycode == KEY_RESERVED)
> - return;
> + if (new_event && keycode != KEY_RESERVED) {
> + /* Register a keypress */
> + dev->keypressed = true;
> + dev->last_scancode = scancode;
> + dev->last_toggle = toggle;
> + dev->last_keycode = keycode;
> +
> + IR_dprintk(1, "%s: key down event, "
> + "key 0x%04x, scancode 0x%04x\n",
> + dev->input_name, keycode, scancode);
> + input_report_key(dev->input_dev, keycode, 1);
> + }
>
> - /* Register a keypress */
> - dev->keypressed = true;
> - IR_dprintk(1, "%s: key down event, key 0x%04x, scancode 0x%04x\n",
> - dev->input_name, keycode, scancode);
> - input_report_key(dev->input_dev, dev->last_keycode, 1);
> input_sync(dev->input_dev);
> }
>
> --
> 1.7.5.4
>
--
Dmitry
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