Hi Len, On Friday 24 October 2008, Len Brown wrote: > Dmitry, > > Looking around the tree, the other calls to > input_report_switch() and input_report_key() > are all followed by input_sync(). > The idea is that userspace can accumulate input events and not act on them till it gets the "whole state" of the device which is indicated by sending EV_SYN/SYN_REPORT event. This really does not matter for most of the simple devices (such as most button devices) but is required when you need to report state of a touchpad or a tablet (ABS_X, ABS_Y, ABS_PRESSURE, host of buttons and so on). And that is the reason to have 2 input_sync when you you reporting button down and up back to back - if there was only one input_sync userspace may (although I don't think anyone does) wait to reacting till the sync and by that time the up event will "cancel out" the down event. > I guess we didn't understand the API when we added > these calls to button.c? > The code was fine until acpi_lid_send_state was used un resume path, then it needed its own input_sync. > Looks like the other users of input_report_* in > drivers/acpi and drivers/misc are okay, > with the exception of toshiba_acpi.c -- > the most neglected driver we have, > so I"ll do the same to that one? > > Ack? Yep. > > thanks, > -Len > > > On Fri, 24 Oct 2008, Guillem Jover wrote: > > > Currently not always an EV_SYN event is reported to userland > > after the EV_SW SW_LID event has been sent. This is easy to verify > > by using “input-events” from input-utils and just closing and opening > > the lid. > > > > Signed-off-by: Guillem Jover <guillem.jover@xxxxxxxxx> > > --- > > drivers/acpi/button.c | 3 ++- > > 1 files changed, 2 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c > > index 1dfec41..59352d9 100644 > > --- a/drivers/acpi/button.c > > +++ b/drivers/acpi/button.c > > @@ -262,6 +262,7 @@ static int acpi_lid_send_state(struct acpi_button *button) > > return -ENODEV; > > /* input layer checks if event is redundant */ > > input_report_switch(button->input, SW_LID, !state); > > + input_sync(button->input); > > return 0; > > } > > > > @@ -285,8 +286,8 @@ static void acpi_button_notify(acpi_handle handle, u32 event, void *data) > > input_report_key(input, keycode, 1); > > input_sync(input); > > input_report_key(input, keycode, 0); > > + input_sync(input); > > } > > - input_sync(input); > > > > acpi_bus_generate_proc_event(button->device, event, > > ++button->pushed); > > -- > > 1.6.0.2 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
