HID: multitouch: do not retrieve all reports for all devices

We already have in place a quirk for Windows 8 devices, but it looks
like the Surface Cover are not conforming to it.
Given that we are only interested in 3 feature reports (the ones that
the Windows driver retrieves), we should be safe to unconditionally apply
the quirk to everybody.

In case there is an issue with a controller, we can always mark it as such
in the transport driver, and hid-multitouch won't try to retrieve the
feature report.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 84c56e645fe87addb93703c61f507da285fae482..89e9032ab1e7446c37b5d4d19c6dfc3ec6498bfd 100644 (file)
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -108,6 +108,7 @@ struct mt_device {
        int cc_value_index;     /* contact count value index in the field */
        unsigned last_slot_field;       /* the last field of a slot */
        unsigned mt_report_id;  /* the report ID of the multitouch device */
+       unsigned long initial_quirks;   /* initial quirks state */
        __s16 inputmode;        /* InputMode HID feature, -1 if non-existent */
        __s16 inputmode_index;  /* InputMode HID feature index in the report */
        __s16 maxcontact_report_id;     /* Maximum Contact Number HID feature,
@@ -318,13 +319,10 @@ static void mt_get_feature(struct hid_device *hdev, struct hid_report *report)
        u8 *buf;
 
        /*
-        * Only fetch the feature report if initial reports are not already
-        * been retrieved. Currently this is only done for Windows 8 touch
-        * devices.
+        * Do not fetch the feature report if the device has been explicitly
+        * marked as non-capable.
         */
-       if (!(hdev->quirks & HID_QUIRK_NO_INIT_REPORTS))
-               return;
-       if (td->mtclass.name != MT_CLS_WIN_8)
+       if (td->initial_quirks & HID_QUIRK_NO_INIT_REPORTS)
                return;
 
        buf = hid_alloc_report_buf(report, GFP_KERNEL);
@@ -1085,36 +1083,6 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
                }
        }
 
-       /* This allows the driver to correctly support devices
-        * that emit events over several HID messages.
-        */
-       hdev->quirks |= HID_QUIRK_NO_INPUT_SYNC;
-
-       /*
-        * This allows the driver to handle different input sensors
-        * that emits events through different reports on the same HID
-        * device.
-        */
-       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.
-                *
-                * In addition some touchpads do not behave well if we read
-                * all feature reports from them. Instead we prevent
-                * initial report fetching and then selectively fetch each
-                * report we are interested in.
-                */
-               hdev->quirks |= HID_QUIRK_NO_INIT_REPORTS;
-
        td = devm_kzalloc(&hdev->dev, sizeof(struct mt_device), GFP_KERNEL);
        if (!td) {
                dev_err(&hdev->dev, "cannot allocate multitouch data\n");
@@ -1138,6 +1106,39 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
        if (id->vendor == HID_ANY_ID && id->product == HID_ANY_ID)
                td->serial_maybe = true;
 
+       /*
+        * Store the initial quirk state
+        */
+       td->initial_quirks = hdev->quirks;
+
+       /* This allows the driver to correctly support devices
+        * that emit events over several HID messages.
+        */
+       hdev->quirks |= HID_QUIRK_NO_INPUT_SYNC;
+
+       /*
+        * This allows the driver to handle different input sensors
+        * that emits events through different reports on the same HID
+        * device.
+        */
+       hdev->quirks |= HID_QUIRK_MULTI_INPUT;
+       hdev->quirks |= HID_QUIRK_NO_EMPTY_INPUT;
+
+       /*
+        * 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. For Win7 devices, well, let's hope
+        * they will still be happy (this is only be a problem if a touch
+        * was already there while probing the device).
+        *
+        * In addition some touchpads do not behave well if we read
+        * all feature reports from them. Instead we prevent
+        * initial report fetching and then selectively fetch each
+        * report we are interested in.
+        */
+       hdev->quirks |= HID_QUIRK_NO_INIT_REPORTS;
+
        ret = hid_parse(hdev);
        if (ret != 0)
                return ret;
@@ -1206,8 +1207,11 @@ static int mt_resume(struct hid_device *hdev)
 
 static void mt_remove(struct hid_device *hdev)
 {
+       struct mt_device *td = hid_get_drvdata(hdev);
+
        sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group);
        hid_hw_stop(hdev);
+       hdev->quirks = td->initial_quirks;
 }
 
 /*