Kernel sometimes reports negated device ID #134

jigpu · 2019-10-31T21:25:55Z

I want to understand more about what the hardware is sending to cause our kernel driver to send both 0x807B and then later 0xFFFF807B.

See the following patch:

diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
index 5ded94b7bf68..6b529d54f334 100644
--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -272,10 +272,10 @@ static void wacom_hid_usage_quirk(struct hid_device *hdev,
 		    b->report_size == 8) {
 			features->quirks |= WACOM_QUIRK_AESPEN;
 			usage->hid = WACOM_HID_WD_TOOLTYPE;
-			field->logical_minimum = S16_MIN;
-			field->logical_maximum = S16_MAX;
-			a->logical_minimum = S32_MIN;
-			a->logical_maximum = S32_MAX;
+			field->logical_minimum = 0;
+			field->logical_maximum = U16_MAX;
+			a->logical_minimum = 0;
+			a->logical_maximum = U32_MAX;
 			b->usage[0].hid = WACOM_HID_WD_SERIALHI;
 			b->logical_minimum = 0;
 			b->logical_maximum = U8_MAX;

The issue is that hid-core converts the signed 16 bits value into a signed 32 bits. However, in wacom-wac.c the code interprets this as an unsigned, which adds 0xffff0000 to the value.

In wacom_wac_pen_serial_enforce() we call hid_field_extract() without snto32() which leads to the 2 different values during the serial enforcing phase and the normal retrieval of values.

So either we apply my patch above, either we check for min < 0 in wacom_wac_pen_serial_enforce() and append or not snto32().

Actually, we might want to do both: this would prevent future issues for a non modified report descriptor.

My issue is now why gnome-terminal is crashing when I use the pen...

Originally posted by @bentiss in linuxwacom/libwacom#156 (comment)

The text was updated successfully, but these errors were encountered:

The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom#134 Fixes: f85c9dc678 ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.9+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>

AES sensors use protocol 5 since they send ABS_MISC events which contain information about the tool type in use. The tool type information sent by AES sensors does not match that used by EMR sensors, however. In particular, it is not possible to extract stylus/eraser/puck information from the ID. The driver would normally never try to extract this information, but the problem was highlighed when a bug in the kernel would cause the device ID to be reported twice: once in a packet alongside a BTN_TOOL_* event (fine) and a second time in a packet without such an event (causing the driver to try to figure it out from the ID instead). This commit adds detection for AES pen IDs and does not try to extract such information if an AES pen is in use. Ref: linuxwacom/input-wacom#134 Fixes: linuxwacom#74 Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>

AES sensors use protocol 5 since they send ABS_MISC events which contain information about the tool type in use. The tool type information sent by AES sensors does not match that used by EMR sensors, however. In particular, it is not possible to extract stylus/eraser/puck information from the ID. The driver would normally never try to extract this information, but the problem was highlighed when a bug in the kernel would cause the device ID to be reported twice: once in a packet alongside a BTN_TOOL_* event (fine) and a second time in a packet without such an event (causing the driver to try to figure it out from the ID instead). This commit adds detection for AES pen IDs and does not try to extract such information if an AES pen is in use. We assume that any protocol 5 device which predates the use of Intuos5-era technology uses the legacy IDs. Ref: linuxwacom/input-wacom#134 Fixes: linuxwacom#74 Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>

The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>

commit ff47973 upstream. The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit ff479731c3859609530416a18ddb3db5db019b66 upstream. The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit ff47973 upstream. The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit ff479731c3859609530416a18ddb3db5db019b66 upstream. The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc678 ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Source: Kernel.org MR: 100551 Type: Integration Disposition: Backport from git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable linux-4.19.y ChangeID: a81a4637456b75e6e2b2a81911c4ea960c7f8cae Description: commit ff479731c3859609530416a18ddb3db5db019b66 upstream. The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Armin Kuster <akuster@mvista.com>

Source: Kernel.org MR: 100559 Type: Integration Disposition: Backport from git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable linux-4.14.y ChangeID: ab19c1ddaa02c8a99dffcec578ec30979e853e22 Description: commit ff479731c3859609530416a18ddb3db5db019b66 upstream. The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Armin Kuster <akuster@mvista.com>

commit ff479731c3859609530416a18ddb3db5db019b66 upstream. The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: #134 Fixes: f85c9dc678 ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> [jason.gerecke@wacom.com: Imported into input-wacom repository (ff479731c385)] Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>

… as unsigned The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: #134 Fixes: f85c9dc678 ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> [jason.gerecke@wacom.com: Imported into input-wacom repository (ff479731c385)] Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> [jason.gerecke@wacom.com: Backported from input-wacom repository (71218c6)] Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>

commit ff479731c3859609530416a18ddb3db5db019b66 upstream. The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit ff479731c3859609530416a18ddb3db5db019b66 upstream. The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc678 ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit ff47973 upstream. The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

BugLink: https://bugs.launchpad.net/bugs/1852338 commit ff47973 upstream. The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com> Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

commit ff479731c3859609530416a18ddb3db5db019b66 upstream. The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit ff479731c3859609530416a18ddb3db5db019b66 upstream. The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc678 ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit ff47973 upstream. The HID descriptors for most Wacom devices oddly declare the serial number and other related fields as signed integers. When these numbers are ingested by the HID subsystem, they are automatically sign-extended into 32-bit integers. We treat the fields as unsigned elsewhere in the kernel and userspace, however, so this sign-extension causes problems. In particular, the sign-extended tool ID sent to userspace as ABS_MISC does not properly match unsigned IDs used by xf86-input-wacom and libwacom. We introduce a function 'wacom_s32tou' that can undo the automatic sign extension performed by 'hid_snto32'. We call this function when processing the serial number and related fields to ensure that we are dealing with and reporting the unsigned form. We opt to use this method rather than adding a descriptor fixup in 'wacom_hid_usage_quirk' since it should be more robust in the face of future devices. Ref: linuxwacom/input-wacom#134 Fixes: f85c9dc ("HID: wacom: generic: Support tool ID and additional tool types") CC: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>