At Hikey 970, setting the SPLIT disable at the General User Register 3 is required. Without that, the URBs generated by the usbhid driver return -EPROTO errors. That causes the code at hid-core.c to call hid_io_error(), which schedules a reset_work, causing a call to hid_reset(). In turn, the code there will call: usb_queue_reset_device(usbhid->intf); The net result is that the input devices won't work, and will be reset on every 0.5 seconds: [ 33.122384] hub 1-1:1.0: state 7 ports 4 chg 0000 evt 0002 [ 33.378220] usb 1-1.1: reset low-speed USB device number 3 using xhci-hcd [ 33.698394] hub 1-1:1.0: state 7 ports 4 chg 0000 evt 0000 [ 34.882365] hub 1-1:1.0: state 7 ports 4 chg 0000 evt 0002 [ 35.138217] usb 1-1.1: reset low-speed USB device number 3 using xhci-hcd [ 35.458617] hub 1-1:1.0: state 7 ports 4 chg 0000 evt 0000 [ 36.642392] hub 1-1:1.0: state 7 ports 4 chg 0000 evt 0002 [ 36.898207] usb 1-1.1: reset low-speed USB device number 3 using xhci-hcd [ 37.218598] hub 1-1:1.0: state 7 ports 4 chg 0000 evt 0000 [ 38.402368] hub 1-1:1.0: state 7 ports 4 chg 0000 evt 0002 [ 38.658174] usb 1-1.1: reset low-speed USB device number 3 using xhci-hcd [ 38.978594] hub 1-1:1.0: state 7 ports 4 chg 0000 evt 0000 [ 40.162361] hub 1-1:1.0: state 7 ports 4 chg 0000 evt 0002 [ 40.418148] usb 1-1.1: reset low-speed USB device number 3 using xhci-hcd ... [ 397.698132] usb 1-1.1: reset low-speed USB device number 3 using xhci-hcd Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> --- Documentation/devicetree/bindings/usb/dwc3.txt | 3 +++ 1 file changed, 3 insertions(+) diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt index d03edf9d3935..1aae2b6160c1 100644 --- a/Documentation/devicetree/bindings/usb/dwc3.txt +++ b/Documentation/devicetree/bindings/usb/dwc3.txt @@ -78,6 +78,9 @@ Optional properties: park mode are disabled. - snps,dis_metastability_quirk: when set, disable metastability workaround. CAUTION: use only if you are absolutely sure of it. + - snps,dis-split-quirk: when set, change the way URBs are handled by the + driver. Needed to avoid -EPROTO errors with usbhid + on some devices (Hikey 970). - snps,is-utmi-l1-suspend: true when DWC3 asserts output signal utmi_l1_suspend_n, false when asserts utmi_sleep_n - snps,hird-threshold: HIRD threshold -- 2.26.2
