HID: do not init input reports for Win 8 multitouch devices

Some multitouch screens do not like to be polled for input reports.
However, the Win8 spec says that all touches should be sent during
each report, making the initialization of reports unnecessary.
The Win7 spec is less precise, so do not use this for those devices.

Add the quirk HID_QUIRK_NO_INIT_INPUT_REPORTS so that we do not have to
introduce a quirk for each problematic device. This quirk makes the driver
behave the same way the Win 8 does. It actually retrieves the features,
but not the inputs.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: Henrik Rydberg <rydberg@euromail.se>
Tested-by: Srinivas Pandruvada<srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

3 files changed, 21 insertions, 3 deletions

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index c28ef86c7c67..ac28f08c3866 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -951,6 +951,18 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
         hdev->quirks |= HID_QUIRK_MULTI_INPUT;
         hdev->quirks |= HID_QUIRK_NO_EMPTY_INPUT;
 
+        /*
+         * Handle special quirks for Windows 8 certified devices.
+         */
+        if (id->group == HID_GROUP_MULTITOUCH_WIN_8)
+                /*
+                 * Some multitouch screens do not like to be polled for input
+                 * reports. Fortunately, the Win8 spec says that all touches
+                 * should be sent during each report, making the initialization
+                 * of input reports unnecessary.
+                 */
+                hdev->quirks |= HID_QUIRK_NO_INIT_INPUT_REPORTS;
+
         td = devm_kzalloc(&hdev->dev, sizeof(struct mt_device), GFP_KERNEL);
         if (!td) {
                 dev_err(&hdev->dev, "cannot allocate multitouch data\n");
diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
index 99418285222c..55ea9c40140e 100644
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -807,12 +807,17 @@ void usbhid_init_reports(struct hid_device *hid)
 {
         struct hid_report *report;
         struct usbhid_device *usbhid = hid->driver_data;
+        struct hid_report_enum *report_enum;
         int err, ret;
 
-        list_for_each_entry(report, &hid->report_enum[HID_INPUT_REPORT].report_list, list)
-                usbhid_submit_report(hid, report, USB_DIR_IN);
+        if (!(hid->quirks & HID_QUIRK_NO_INIT_INPUT_REPORTS)) {
+                report_enum = &hid->report_enum[HID_INPUT_REPORT];
+                list_for_each_entry(report, &report_enum->report_list, list)
+                        usbhid_submit_report(hid, report, USB_DIR_IN);
+        }
 
-        list_for_each_entry(report, &hid->report_enum[HID_FEATURE_REPORT].report_list, list)
+        report_enum = &hid->report_enum[HID_FEATURE_REPORT];
+        list_for_each_entry(report, &report_enum->report_list, list)
                 usbhid_submit_report(hid, report, USB_DIR_IN);
 
         err = 0;
diff --git a/include/linux/hid.h b/include/linux/hid.h
index cef1e9b86cc4..bc132d2a20aa 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -283,6 +283,7 @@ struct hid_item {
 #define HID_QUIRK_MULTI_INPUT                   0x00000040
 #define HID_QUIRK_HIDINPUT_FORCE                0x00000080
 #define HID_QUIRK_NO_EMPTY_INPUT                0x00000100
+#define HID_QUIRK_NO_INIT_INPUT_REPORTS         0x00000200
 #define HID_QUIRK_SKIP_OUTPUT_REPORTS           0x00010000
 #define HID_QUIRK_FULLSPEED_INTERVAL            0x10000000
 #define HID_QUIRK_NO_INIT_REPORTS               0x20000000