drivers: hid: renegotiate resolution multipliers with device after reset

The scroll resolution multipliers are set in the context of
hidinput_connect(), which is only called at probe time: when the host
changes the value on the device with a SET_REPORT(FEATURE), and the device
accepts it, these multipliers are stored on the host side, and used to
calculate the final scroll event values sent to userspace.

After a USB suspend, the resume operation on many hubs and chipsets
involve a USB reset signal as well. A reset on the device side clears all
previous state information, including the value of the multiplier report.
This reset is not handled by the multiplier handling logic, so what ends up
happening is the host is still expecting high-resolution scroll events,
but the device is reset to default resolution, making the effective,
user-perceived scroll speed incredibly slow.

The solution is to renegotiate the multiplier selection after each reset.

This is not the only bug related to the high-resolution scrolling
implementation in the kernel (the other one is
https://bugzilla.kernel.org/show_bug.cgi?id=220144), but for this one,
there is no device side workaround for, leading to poor user experience with our product:
https://github.com/UltimateHackingKeyboard/firmware/issues/1155
https://github.com/UltimateHackingKeyboard/firmware/issues/1261
https://github.com/UltimateHackingKeyboard/firmware/pull/1355
This patch was tested by an affected user and has been reported to
fix the issue (see discussion in 1355).

Signed-off-by: Benedek Kupper <kupper.benedek@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

diff --git a/drivers/hid/hid-generic.c b/drivers/hid/hid-generic.c
index 9e04c6d0fcc874e8b6e5c1abffd48d44cfebcb43..c2de916747dec8c3734f8c2ce17ca87cee1ac82b 100644 (file)
--- a/drivers/hid/hid-generic.c
+++ b/drivers/hid/hid-generic.c
@@ -70,6 +70,14 @@ static int hid_generic_probe(struct hid_device *hdev,
        return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
 }
 
+static int hid_generic_reset_resume(struct hid_device *hdev)
+{
+       if (hdev->claimed & HID_CLAIMED_INPUT)
+               hidinput_reset_resume(hdev);
+
+       return 0;
+}
+
 static const struct hid_device_id hid_table[] = {
        { HID_DEVICE(HID_BUS_ANY, HID_GROUP_ANY, HID_ANY_ID, HID_ANY_ID) },
        { }
@@ -81,6 +89,7 @@ static struct hid_driver hid_generic = {
        .id_table = hid_table,
        .match = hid_generic_match,
        .probe = hid_generic_probe,
+       .reset_resume = hid_generic_reset_resume,
 };
 module_hid_driver(hid_generic);
 

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 2bbb645c2ff418d108e2ac26e91578ee8c2d7452..9f899ee83f0be09235dbb5b5d92b4b3888dfb6fc 100644 (file)
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -2400,6 +2400,13 @@ void hidinput_disconnect(struct hid_device *hid)
 }
 EXPORT_SYMBOL_GPL(hidinput_disconnect);
 
+void hidinput_reset_resume(struct hid_device *hid)
+{
+       /* renegotiate host-device shared state after reset */
+       hidinput_change_resolution_multipliers(hid);
+}
+EXPORT_SYMBOL_GPL(hidinput_reset_resume);
+
 #ifdef CONFIG_HID_KUNIT_TEST
 #include "hid-input-test.c"
 #endif

diff --git a/include/linux/hid.h b/include/linux/hid.h
index a4ddb94e3ee5632d4fb6667d6aed2048918c8978..dce862cafbbd35b29abd7be95290bac5d9daee8b 100644 (file)
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -984,6 +984,7 @@ extern void hidinput_hid_event(struct hid_device *, struct hid_field *, struct h
 extern void hidinput_report_event(struct hid_device *hid, struct hid_report *report);
 extern int hidinput_connect(struct hid_device *hid, unsigned int force);
 extern void hidinput_disconnect(struct hid_device *);
+void hidinput_reset_resume(struct hid_device *hid);
 
 struct hid_field *hid_find_field(struct hid_device *hdev, unsigned int report_type,
                                 unsigned int application, unsigned int usage);