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| author | Jason Gerecke <jason.gerecke@wacom.com> | 2020-09-23 22:14:56 +0200 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2020-09-25 13:14:16 +0200 |
| commit | d9216d753b2b1406b801243b12aaf00a5ce5b861 (patch) | |
| tree | 13386f866f8d72ea30eb8d7860c75dcf82c6cb5e /drivers | |
| parent | HID: i2c-hid: fix kerneldoc warnings in i2c-hid-core.c (diff) | |
| download | linux-d9216d753b2b1406b801243b12aaf00a5ce5b861.tar.xz linux-d9216d753b2b1406b801243b12aaf00a5ce5b861.zip | |
HID: wacom: Avoid entering wacom_wac_pen_report for pad / battery
It has recently been reported that the "heartbeat" report from devices
like the 2nd-gen Intuos Pro (PTH-460, PTH-660, PTH-860) or the 2nd-gen
Bluetooth-enabled Intuos tablets (CTL-4100WL, CTL-6100WL) can cause the
driver to send a spurious BTN_TOUCH=0 once per second in the middle of
drawing. This can result in broken lines while drawing on Chrome OS.
The source of the issue has been traced back to a change which modified
the driver to only call `wacom_wac_pad_report()` once per report instead
of once per collection. As part of this change, pad-handling code was
removed from `wacom_wac_collection()` under the assumption that the
`WACOM_PEN_FIELD` and `WACOM_TOUCH_FIELD` checks would not be satisfied
when a pad or battery collection was being processed.
To be clear, the macros `WACOM_PAD_FIELD` and `WACOM_PEN_FIELD` do not
currently check exclusive conditions. In fact, most "pad" fields will
also appear to be "pen" fields simply due to their presence inside of
a Digitizer application collection. Because of this, the removal of
the check from `wacom_wac_collection()` just causes pad / battery
collections to instead trigger a call to `wacom_wac_pen_report()`
instead. The pen report function in turn resets the tip switch state
just prior to exiting, resulting in the observed BTN_TOUCH=0 symptom.
To correct this, we restore a version of the `WACOM_PAD_FIELD` check
in `wacom_wac_collection()` and return early. This effectively prevents
pad / battery collections from being reported until the very end of the
report as originally intended.
Fixes: d4b8efeb46d9 ("HID: wacom: generic: Correct pad syncing")
Cc: stable@vger.kernel.org # v4.17+
Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Reviewed-by: Ping Cheng <ping.cheng@wacom.com>
Tested-by: Ping Cheng <ping.cheng@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/hid/wacom_wac.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c index 1c96809b51c9..b74acbd5997b 100644 --- a/drivers/hid/wacom_wac.c +++ b/drivers/hid/wacom_wac.c @@ -2773,7 +2773,9 @@ static int wacom_wac_collection(struct hid_device *hdev, struct hid_report *repo if (report->type != HID_INPUT_REPORT) return -1; - if (WACOM_PEN_FIELD(field) && wacom->wacom_wac.pen_input) + if (WACOM_PAD_FIELD(field)) + return 0; + else if (WACOM_PEN_FIELD(field) && wacom->wacom_wac.pen_input) wacom_wac_pen_report(hdev, report); else if (WACOM_FINGER_FIELD(field) && wacom->wacom_wac.touch_input) wacom_wac_finger_report(hdev, report); |