HID: wacom: fix timeout on probe for some wacoms

Some Wacom tablets (at least the ISDv4 found in the Lenovo X230) timeout
during probe while retrieving the input reports.
The only time this information is valuable is during the feature_mapping
stage, so we can ask for it there and discard the generic input reports
retrieval.

This gives a code path closer to the wacom.ko driver when it was in the
input subtree (not HID).

Cc: stable@vger.kernel.org # requires cherry-pick of c64d883476
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
index a8b7f16f76fae8f96273d4315e134495e10f5521..25086287957e9d435debbef1fa386bc5ddaf18b0 100644 (file)
--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -110,12 +110,24 @@ static void wacom_feature_mapping(struct hid_device *hdev,
 {
        struct wacom *wacom = hid_get_drvdata(hdev);
        struct wacom_features *features = &wacom->wacom_wac.features;
+       u8 *data;
+       int ret;
 
        switch (usage->hid) {
        case HID_DG_CONTACTMAX:
                /* leave touch_max as is if predefined */
-               if (!features->touch_max)
-                       features->touch_max = field->value[0];
+               if (!features->touch_max) {
+                       /* read manually */
+                       data = kzalloc(2, GFP_KERNEL);
+                       if (!data)
+                               break;
+                       data[0] = field->report->id;
+                       ret = wacom_get_report(hdev, HID_FEATURE_REPORT,
+                                               data, 2, 0);
+                       if (ret == 2)
+                               features->touch_max = data[1];
+                       kfree(data);
+               }
                break;
        }
 }
@@ -1280,6 +1292,8 @@ static int wacom_probe(struct hid_device *hdev,
        if (!id->driver_data)
                return -EINVAL;
 
+       hdev->quirks |= HID_QUIRK_NO_INIT_REPORTS;
+
        wacom = kzalloc(sizeof(struct wacom), GFP_KERNEL);
        if (!wacom)
                return -ENOMEM;