From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mika Westerberg Subject: [PATCH] HID: multitouch: Fetch feature reports on demand for Win8 devices Date: Mon, 28 Sep 2015 17:47:10 +0300 Message-ID: <1443451630-144023-1-git-send-email-mika.westerberg@linux.intel.com> Return-path: Received: from mga03.intel.com ([134.134.136.65]:9781 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933318AbbI1OrN (ORCPT ); Mon, 28 Sep 2015 10:47:13 -0400 Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Jiri Kosina Cc: Benjamin Tissoires , Mika Westerberg , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org 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 Signed-off-by: Mika Westerberg --- This is a second version. The first one which just prevented initial report reading can be found here: https://lkml.org/lkml/2015/9/24/191 This version tries to do what Benjamin suggested by reading feature values as needed in mt_feature_mapping(). This fixes the issue in the Dell laptop I have here. drivers/hid/hid-multitouch.c | 42 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 41 insertions(+), 1 deletion(-) diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c index 661b4fce1a5d..d9ca2b96ab68 100644 --- a/drivers/hid/hid-multitouch.c +++ b/drivers/hid/hid-multitouch.c @@ -309,6 +309,38 @@ static struct attribute_group mt_attribute_group = { .attrs = sysfs_attrs }; +static void mt_get_feature(struct hid_device *hdev, struct hid_report *report) +{ + 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; + + 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 +359,8 @@ 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 +377,7 @@ 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 +1064,13 @@ 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) { -- 2.5.1