HID: multitouch: Fetch feature reports on demand for Win8 devices
authorMika Westerberg <mika.westerberg@linux.intel.com>
Wed, 7 Oct 2015 12:33:43 +0000 (15:33 +0300)
committerJiri Kosina <jkosina@suse.cz>
Sun, 11 Oct 2015 22:49:19 +0000 (00:49 +0200)
Some newer Intel Skylake based Dell laptops with Win8 precision touchpad
fail when initial feature reports are fetched from it. Below is an example
output with some additional debug included:

 i2c_hid i2c-DLL0704:01: Fetching the HID descriptor
 i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=20 00
 i2c_hid i2c-DLL0704:01: HID Descriptor: 1e 00 00 01 99 02 21 00 24 ...
 ...
 i2c_hid i2c-DLL0704:01: i2c_hid_get_report
 i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=22 00 38 02 23 00
 i2c_hid i2c-DLL0704:01: report (len=4): 04 00 08 05
 i2c_hid i2c-DLL0704:01: report id 13
 i2c_hid i2c-DLL0704:01: i2c_hid_get_report
 i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=22 00 3d 02 23 00
 i2c_hid i2c-DLL0704:01: failed to retrieve report from device.
 i2c_hid i2c-DLL0704:01: report id 7
 i2c_hid i2c-DLL0704:01: i2c_hid_get_report
 i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=22 00 37 02 23 00
 i2c_hid i2c-DLL0704:01: report (len=259): 03 01 07 fc 28 fe 84 40 ...
 i2c_hid i2c-DLL0704:01: report id 4
 i2c_hid i2c-DLL0704:01: i2c_hid_get_report
 i2c_hid i2c-DLL0704:01: __i2c_hid_command: cmd=22 00 34 02 23 00

We manage to fetch few reports but then the touchpad dies:

 i2c_designware i2c_designware.1: i2c_dw_handle_tx_abort: lost arbitration
 i2c_hid i2c-DLL0704:01: failed to retrieve report from device.

it eventually pulls the whole I2C bus low:

 i2c_designware i2c_designware.1: controller timed out
 i2c_hid i2c-DLL0704:01: failed to set a report to device.

Fix this by preventing initial feature report retrieval for Win8 devices.
Instead we fetch reports as needed in mt_feature_mapping(). This prevents
fetching reports which might cause problems with the device in question.

Suggested-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Tested-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
drivers/hid/hid-multitouch.c

index 661b4fce1a5dd753eba3ba122bac453def01e26e..dd64461e5e858eabc8ec9c09bc0406f751392321 100644 (file)
@@ -309,6 +309,41 @@ static struct attribute_group mt_attribute_group = {
        .attrs = sysfs_attrs
 };
 
+static void mt_get_feature(struct hid_device *hdev, struct hid_report *report)
+{
+       struct mt_device *td = hid_get_drvdata(hdev);
+       int ret, size = hid_report_len(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.
+        */
+       if (!(hdev->quirks & HID_QUIRK_NO_INIT_REPORTS))
+               return;
+       if (td->mtclass.name != MT_CLS_WIN_8)
+               return;
+
+       buf = hid_alloc_report_buf(report, GFP_KERNEL);
+       if (!buf)
+               return;
+
+       ret = hid_hw_raw_request(hdev, report->id, buf, size,
+                                HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
+       if (ret < 0) {
+               dev_warn(&hdev->dev, "failed to fetch feature %d\n",
+                        report->id);
+       } else {
+               ret = hid_report_raw_event(hdev, HID_FEATURE_REPORT, buf,
+                                          size, 0);
+               if (ret)
+                       dev_warn(&hdev->dev, "failed to report feature\n");
+       }
+
+       kfree(buf);
+}
+
 static void mt_feature_mapping(struct hid_device *hdev,
                struct hid_field *field, struct hid_usage *usage)
 {
@@ -327,6 +362,8 @@ static void mt_feature_mapping(struct hid_device *hdev,
 
                break;
        case HID_DG_CONTACTMAX:
+               mt_get_feature(hdev, field->report);
+
                td->maxcontact_report_id = field->report->id;
                td->maxcontacts = field->value[0];
                if (!td->maxcontacts &&
@@ -343,6 +380,7 @@ static void mt_feature_mapping(struct hid_device *hdev,
                        break;
                }
 
+               mt_get_feature(hdev, field->report);
                if (field->value[usage->usage_index] == MT_BUTTONTYPE_CLICKPAD)
                        td->is_buttonpad = true;
 
@@ -1029,8 +1067,13 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
                 * 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_INPUT_REPORTS;
+               hdev->quirks |= HID_QUIRK_NO_INIT_REPORTS;
 
        td = devm_kzalloc(&hdev->dev, sizeof(struct mt_device), GFP_KERNEL);
        if (!td) {