On Wed, 7 Oct 2015, Mika Westerberg wrote: > 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> > --- > Added check for MT_CLS_WIN_8 so that the fix is only done for real Win8 > devices. This is now in hid.git#for-4.4/multitouch. Thanks everybody, -- Jiri Kosina SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
