From 286f3f478796fb4f9e003e9f7d649f3c33f08d2f Mon Sep 17 00:00:00 2001 From: Jason Gerecke Date: Thu, 13 Apr 2017 08:39:49 -0700 Subject: [PATCH 1/2] HID: wacom: Treat HID_DG_TOOLSERIALNUMBER as unsigned Because HID_DG_TOOLSERIALNUMBER doesn't first cast the value recieved from HID to an unsigned type, sign-extension rules can cause the value of wacom_wac->serial[0] to inadvertently wind up with all 32 of its highest bits set if the highest bit of "value" was set. This can cause problems for Tablet PC devices which use AES sensors and the xf86-input-wacom userspace driver. It is not uncommon for AES sensors to send a serial number of '0' while the pen is entering or leaving proximity. The xf86-input-wacom driver ignores events with a serial number of '0' since it cannot match them up to an in-use tool. To ensure the xf86-input-wacom driver does not ignore the final out-of-proximity event, the kernel does not send MSC_SERIAL events when the value of wacom_wac->serial[0] is '0'. If the highest bit of HID_DG_TOOLSERIALNUMBER is set by an in-prox pen which later leaves proximity and sends a '0' for HID_DG_TOOLSERIALNUMBER, then only the lowest 32 bits of wacom_wac->serial[0] are actually cleared, causing the kernel to send an MSC_SERIAL event. Since the 'input_event' function takes an 'int' as argument, only those lowest (now-cleared) 32 bits of wacom_wac->serial[0] are sent to userspace, causing xf86-input-wacom to ignore the event. If the event was the final out-of-prox event, then xf86-input-wacom may remain in a state where it believes the pen is in proximity and refuses to allow other devices under its control (e.g. the touchscreen) to move the cursor. It should be noted that EMR devices and devices which use both the HID_DG_TOOLSERIALNUMBER and WACOM_HID_WD_SERIALHI usages (in that order) would be immune to this issue. It appears only AES devices are affected. Fixes: f85c9dc678a ("HID: wacom: generic: Support tool ID and additional tool types") Cc: stable@vger.kernel.org Signed-off-by: Jason Gerecke Acked-by: Benjamin Tissoires Signed-off-by: Jiri Kosina --- drivers/hid/wacom_wac.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c index 94250c293be2..603f7fcd8df6 100644 --- a/drivers/hid/wacom_wac.c +++ b/drivers/hid/wacom_wac.c @@ -2006,7 +2006,7 @@ static void wacom_wac_pen_event(struct hid_device *hdev, struct hid_field *field return; case HID_DG_TOOLSERIALNUMBER: wacom_wac->serial[0] = (wacom_wac->serial[0] & ~0xFFFFFFFFULL); - wacom_wac->serial[0] |= value; + wacom_wac->serial[0] |= (__u32)value; return; case WACOM_HID_WD_SENSE: wacom_wac->hid_data.sense_state = value; From 6f107fab8f18228936cd3df88a3bb6050865c2c8 Mon Sep 17 00:00:00 2001 From: Jason Gerecke Date: Wed, 19 Apr 2017 14:47:24 -0700 Subject: [PATCH 2/2] HID: wacom: Override incorrect logical maximum contact identifier It apears that devices designed around Wacom's G11 chipset (e.g. Lenovo ThinkPad Yoga 260, Lenovo ThinkPad X1 Yoga, Dell XPS 12 9250, Dell Venue 8 Pro 5855, etc.) suffer from a common issue in their HID descriptors. The logical maximum is not updated for the "Contact Identifier" usage, leaving it as just "1" despite these devices being capable of tracking far more touches. Commit 60a221869803 began ignoring usages with out-of-range values, causing problems for devices based on this chipset. Touches after the first will have an out-of-range Contact Identifier, and ignoring that usage will cause the kernel to incorrectly slot each finger's events (along with all the knock-on userspace effects that entails). This commit checks for these buggy descriptors and updates the maximum where required. Prior chipsets have used "255" as the maximum (and the G11, at least, doesn't seem to actually use IDs outside the range of 1..CONTACTMAX) so continue using this value. Cc: stable@vger.kernel.org Fixes: 60a221869803 ("HID: wacom: generic: add support for touchring") Signed-off-by: Jason Gerecke Signed-off-by: Jiri Kosina --- drivers/hid/wacom_wac.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c index 603f7fcd8df6..c68ac65db7ff 100644 --- a/drivers/hid/wacom_wac.c +++ b/drivers/hid/wacom_wac.c @@ -2176,6 +2176,16 @@ static void wacom_wac_finger_usage_mapping(struct hid_device *hdev, wacom_wac->hid_data.cc_index = field->index; wacom_wac->hid_data.cc_value_index = usage->usage_index; break; + case HID_DG_CONTACTID: + if ((field->logical_maximum - field->logical_minimum) < touch_max) { + /* + * The HID descriptor for G11 sensors leaves logical + * maximum set to '1' despite it being a multitouch + * device. Override to a sensible number. + */ + field->logical_maximum = 255; + } + break; } }