2014-12-11 10:02:27

by Peter Wu

Subject: About "HID: logitech-hidpp: add support of the first Logitech Wireless Touchpad"

Hi Benjamin,

In commit 57ac86cf52e903d9e3e0f12b34c814cce6b65550 ("HID:
logitech-hidpp: add support of the first Logitech Wireless Touchpad")
which is in jikos/hid, you made this change to wtp_raw_event:

switch (data[0]) {
case 0x02:
- if (size < 21)
- return 1;
- return wtp_mouse_raw_xy_event(hidpp, &data[7]);
+ if (hidpp->quirks & HIDPP_QUIRK_WTP_PHYSICAL_BUTTONS) {
+ input_event(wd->input, EV_KEY, BTN_LEFT,
+ !!(data[1] & 0x01));
+ input_event(wd->input, EV_KEY, BTN_RIGHT,
+ !!(data[1] & 0x02));
+ input_sync(wd->input);
+ } else {
+ if (size < 21)
+ return 1;
+ return wtp_mouse_raw_xy_event(hidpp, &data[7]);
+ }
case REPORT_ID_HIDPP_LONG:
if ((report->fap.feature_index != wd->mt_feature_index) ||
(report->fap.funcindex_clientid != EVENT_TOUCHPAD_RAW_XY))
return 1;
hidpp_touchpad_raw_xy_event(hidpp, data + 4, &raw);

wtp_send_raw_xy_event(hidpp, &raw);
return 0;
}

Report ID 2 is the mouse descriptor, so it seems correct in that it
falls-through to the next case, but I wanted to check with you that this
is indeed your intention. If so, could you explicitly mark it with a
comment, /* fallthrough */ ?
--
Kind regards,
Peter
https://lekensteyn.nl

2014-12-11 15:19:47

by Benjamin Tissoires

Subject: Re: About "HID: logitech-hidpp: add support of the first Logitech Wireless Touchpad"

Hi Peter,

On Dec 11 2014 or thereabouts, Peter Wu wrote:
> Hi Benjamin,
>
> In commit 57ac86cf52e903d9e3e0f12b34c814cce6b65550 ("HID:
> logitech-hidpp: add support of the first Logitech Wireless Touchpad")
> which is in jikos/hid, you made this change to wtp_raw_event:
>
> switch (data[0]) {
> case 0x02:
> - if (size < 21)
> - return 1;
> - return wtp_mouse_raw_xy_event(hidpp, &data[7]);
> + if (hidpp->quirks & HIDPP_QUIRK_WTP_PHYSICAL_BUTTONS) {
> + input_event(wd->input, EV_KEY, BTN_LEFT,
> + !!(data[1] & 0x01));
> + input_event(wd->input, EV_KEY, BTN_RIGHT,
> + !!(data[1] & 0x02));
> + input_sync(wd->input);
> + } else {
> + if (size < 21)
> + return 1;
> + return wtp_mouse_raw_xy_event(hidpp, &data[7]);
> + }
> case REPORT_ID_HIDPP_LONG:
> if ((report->fap.feature_index != wd->mt_feature_index) ||
> (report->fap.funcindex_clientid != EVENT_TOUCHPAD_RAW_XY))
> return 1;
> hidpp_touchpad_raw_xy_event(hidpp, data + 4, &raw);
>
> wtp_send_raw_xy_event(hidpp, &raw);
> return 0;
> }
>
> Report ID 2 is the mouse descriptor, so it seems correct in that it
> falls-through to the next case, but I wanted to check with you that this
> is indeed your intention. If so, could you explicitly mark it with a
> comment, /* fallthrough */ ?

Yep, it is indeed a bug. I see what happened:
The old code contained a return at the end of the case, and I completely
forget to prevent the fall through with a break. Gosh, I should have
been more careful. Thanks for spotting that!

Cheers,
Benjamin

> --
> Kind regards,
> Peter
> https://lekensteyn.nl
>