Ok, I know why no one follow-up with my patch. Life wasn't as simple
as I wished for :).
The patch missed one important fact: repeated events don't go into
userland. They are filtered! We need to initiate another input_dev to
hold all the past events for the coming tool, whether it is PEN or
RUBBER. So, it is more like a simplified multi-pen case, right? What's
your suggestions? Do we claim two tools for this particular use case?
On Wed, Oct 27, 2021 at 12:06 PM Ping Cheng <pinglinux@xxxxxxxxx> wrote:
>
> Hi @Dmitry Torokhov and @Benjamin Tissoires,
>
> Do you have any comments about this patch? The issue and the logic
> behind the fix has been explained in the commit comment and in the
> code. Jiri is probably waiting for an acknowledgment from one of
> you...
>
> Thank you,
> Ping
>
> On Fri, Oct 22, 2021 at 4:29 PM Ping Cheng <pinglinux@xxxxxxxxx> wrote:
> >
> > The HID_QUIRK_INVERT caused BTN_TOOL_RUBBER events were reported at the
> > same time as events for BTN_TOOL_PEN/PENCIL/etc, if HID_QUIRK_INVERT
> > was set by a stylus' sideswitch. The reality is that a pen can only be
> > a stylus (writing/drawing) or an eraser, but not both at the same time.
> > This patch makes that logic correct.
> >
> > CC: stable@xxxxxxxxxxxxxxx # 2.4+
> > Signed-off-by: Ping Cheng <ping.cheng@xxxxxxxxx>
> > Reviewed-by: Jason Gerecke <killertofu@xxxxxxxxx>
> > Tested-by: Tatsunosuke Tobita <junkpainting@xxxxxxxxx>
> > ---
> > drivers/hid/hid-input.c | 24 ++++++++++++++++++++----
> > 1 file changed, 20 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
> > index 4b5ebeacd283..85741a2d828d 100644
> > --- a/drivers/hid/hid-input.c
> > +++ b/drivers/hid/hid-input.c
> > @@ -1344,12 +1344,28 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct
> > }
> >
> > if (usage->hid == HID_DG_INRANGE) {
> > + /* when HID_QUIRK_INVERT is set by a stylus sideswitch, HID_DG_INRANGE could be
> > + * for stylus or eraser. Make sure events are only posted to the current valid tool:
> > + * BTN_TOOL_RUBBER vs BTN_TOOL_PEN/BTN_TOOL_PENCIL/BTN_TOOL_BRUSH/etc since a pen
> > + * can not be used as a stylus (to draw/write) and an erasaer at the same time
> > + */
> > + static unsigned int last_code = 0;
> > + unsigned int code = (*quirks & HID_QUIRK_INVERT) ? BTN_TOOL_RUBBER : usage->code;
> > if (value) {
> > - input_event(input, usage->type, (*quirks & HID_QUIRK_INVERT) ? BTN_TOOL_RUBBER : usage->code, 1);
> > - return;
> > + if (code != last_code) {
> > + /* send the last tool out before allow the new one in */
> > + if (last_code)
> > + input_event(input, usage->type, last_code, 0);
> > + input_event(input, usage->type, code, 1);
> > + }
> > + last_code = code;
> > + } else {
> > + /* only send the last valid tool out */
> > + if (last_code)
> > + input_event(input, usage->type, last_code, 0);
> > + /* reset tool for next cycle */
> > + last_code = 0;
> > }
> > - input_event(input, usage->type, usage->code, 0);
> > - input_event(input, usage->type, BTN_TOOL_RUBBER, 0);
> > return;
> > }
> >
> > --
> > 2.25.1
> >
