On Feb 14 2016 or thereabouts, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > > This is a note to let you know that I've just added the patch titled > > HID: multitouch: Fetch feature reports on demand for Win8 devices > > to the 4.3-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > hid-multitouch-fetch-feature-reports-on-demand-for-win8-devices.patch > and it can be found in the queue-4.3 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@xxxxxxxxxxxxxxx> know about it. Hi Greg, If you backport this to 4.3, I'd like you to pull in 73e7d63 ("HID: multitouch: fix input mode switching on some Elan panels"). The commit added to your stable queue (6d4f5440) revealed a firmware issue on Elan panels that were unnoticed before. Cheers, Benjamin > > > From 6d4f5440a3a2bb2e9d0d582bbf98234e9e9bb095 Mon Sep 17 00:00:00 2001 > From: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > Date: Wed, 7 Oct 2015 15:33:43 +0300 > Subject: HID: multitouch: Fetch feature reports on demand for Win8 devices > > From: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > > commit 6d4f5440a3a2bb2e9d0d582bbf98234e9e9bb095 upstream. > > 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@xxxxxxxxxx> > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > Reviewed-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> > Tested-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx> > Signed-off-by: Jiri Kosina <jkosina@xxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > --- > drivers/hid/hid-multitouch.c | 45 ++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 44 insertions(+), 1 deletion(-) > > --- a/drivers/hid/hid-multitouch.c > +++ b/drivers/hid/hid-multitouch.c > @@ -309,6 +309,41 @@ static struct attribute_group mt_attribu > .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 hi > > 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 hi > break; > } > > + mt_get_feature(hdev, field->report); > if (field->value[usage->usage_index] == MT_BUTTONTYPE_CLICKPAD) > td->is_buttonpad = true; > > @@ -1026,8 +1064,13 @@ static int mt_probe(struct hid_device *h > * 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) { > > > Patches currently in stable-queue which might be from mika.westerberg@xxxxxxxxxxxxxxx are > > queue-4.3/hid-multitouch-fetch-feature-reports-on-demand-for-win8-devices.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html