Re: [PATCH] HID: input: enable Totem on the Dell Canvas 27

From: Benjamin Tissoires
Date: Wed Nov 15 2017 - 07:53:44 EST


On Nov 14 2017 or thereabouts, Dmitry Torokhov wrote:
> On Tue, Nov 14, 2017 at 06:50:43PM +1000, Peter Hutterer wrote:
> > sorry, this one got stuck in my outbox.
> >
> > On Fri, Nov 10, 2017 at 11:26:35AM +0100, Benjamin Tissoires wrote:
> > > The Dell Canvas 27 has a tool that can be put on the surface and acts
> > > as a dial. The firmware processes the detection of the tool and forward
> > > regular HID reports with X, Y, Azimuth, rotation, width/height.
> > >
> > > The firmware also exports Contact ID, Countact Count which may hint that
> > > several totems can be used at the same time, but for now, only allow
> > > one totem at a time.
> > >
> > > We also ignore scan time in hid-input.c because there is not much point
> > > to forward it now given that the indication of the tool being present
> > > is already provided through BTN_TOOL_DIAL.
> > >
> > > We need to add a new BTN_TOOL_DIAL event because the HID mapping
> > > suggests that this tool is aimed at being used by the system and not
> > > the applications. Also this prevents current systemd heuristics to
> > > apply ID_INPUT_TOUCHSCREEN to this new type of devices.
> > >
> > > I mapped Azimuth to ABS_WHEEL to somehow ressemble the Wacom Pads.
> >
> > HID docs indicate this is a full tool rotation, so ABS_RZ would be more
> > appropriate?
> >
> > "Azimuth
> > The counter-clockwise rotation of the cursor about the Z-axis."
>
> Right. We night also want to consider whether we need to convert HID to
> Linux values, as HID is counter-clockwise, and I suspect Linux will be
> clockwise (what do we report for joysticks?), similar to what we had for
> ABS_MT_ORIENTATION.
>
> >
> > But you also say it has rotation, so this is a bit confusing now :)
> > We should also use INPUT_PROP_DIRECT here.
> >
> > > Last, both Width and Heigth are groupped together, the FW reports
> >
> > typo: grouped
> >
> > > similar values for both and we are out of ABS_* events.
> > >
> > > Link: https://bugzilla.redhat.com/show_bug.cgi?id=1511846
> > >
> > > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
> > > ---
> > >
> > > Hi,
> > >
> > > This is probably v4.16 material as we are close to the merge window
> > > (I wouldn't mind it applied in v4.15 though ;-P)
> >
> > I'm going to be annoying here and say I'd like to figure out how to add this
> > to libinput first to figure out what details can go wrong before we merge it
> > and commit to this forever. Hopefully that shouldn't take that long...
> >

I had a chat with Peter this morning. TL;DR is I'll need to rework on
this more heavily to provide the final version with MT axes, and skip
the single device implementation. I have no ideas if the Dell Canvas
can report more than one totem, but the report descriptor would say so,
so we better have a proper implementation instead of having one for
single device capable and one for multiple devices.

I'll probably send a v2 just to address the issues raised here, but it
shouldn't be merged given that user space will not be accepting such
version.

Cheers,
Benjamin

> > > The patch does the job but we probably need to decide if the mappings
> > > I chose are correct.
> > >
> > > For the record, I uploaded some evemu-record traces and hid-recorder
> > > traces in the RH Bz linked above to keep traces of them.
> > > The interesting one is the evemu one for the totem with this patch
> > > applied:
> > > https://bugzilla.redhat.com/attachment.cgi?id=1350389
> > >
> > > Cheers,
> > > Benjamin
> > >
> > > drivers/hid/hid-input.c | 28 +++++++++++++++++++++++++++-
> > > drivers/hid/hid-multitouch.c | 11 +++++++++++
> > > include/linux/hid.h | 6 ++++++
> > > include/uapi/linux/input-event-codes.h | 1 +
> > > 4 files changed, 45 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
> > > index 04d01b57d94c..7da72b571b7d 100644
> > > --- a/drivers/hid/hid-input.c
> > > +++ b/drivers/hid/hid-input.c
> > > @@ -229,6 +229,7 @@ __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code)
> > > case ABS_X:
> > > case ABS_Y:
> > > case ABS_Z:
> > > + case ABS_TOOL_WIDTH:
> > > case ABS_MT_POSITION_X:
> > > case ABS_MT_POSITION_Y:
> > > case ABS_MT_TOOL_X:
> > > @@ -786,13 +787,24 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
> > > map_abs_clear(ABS_TILT_Y);
> > > break;
> > >
> > > + case 0x3f: /* Azimuth */
> > > + map_abs_clear(ABS_WHEEL);
> > > + break;
> > > +
> > > case 0x33: /* Touch */
> > > - case 0x42: /* TipSwitch */
> > > case 0x43: /* TipSwitch2 */
> > > device->quirks &= ~HID_QUIRK_NOTOUCH;
> > > map_key_clear(BTN_TOUCH);
> > > break;
> > >
> > > + case 0x42: /* TipSwitch */
> > > + if (field->application == HID_GD_SYSTEM_MULTIAXIS) {
> > > + map_key_clear(BTN_TOOL_DIAL);
> > > + } else {
> > > + device->quirks &= ~HID_QUIRK_NOTOUCH;
> > > + map_key_clear(BTN_TOUCH);
> > > + }
> > > + break;
> > > case 0x44: /* BarrelSwitch */
> > > map_key_clear(BTN_STYLUS);
> > > break;
> > > @@ -806,6 +818,20 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
> > > map_key_clear(BTN_TOUCH);
> > > break;
> > >
> > > + case 0x48: /* WIDTH */
> > > + case 0x49: /* HEIGHT */
> > > + map_abs_clear(ABS_TOOL_WIDTH);
> > > + break;
> > > +
> > > + case 0x51: /* CONTACT ID */
> > > + goto ignore;
> > > +
> > > + case 0x54: /* CONTACT COUNT */
> > > + goto ignore;
> > > +
> > > + case 0x56: /* SCANTIME */
> > > + goto ignore;
> > > +
> > > case 0x46: /* TabletPick */
> > > case 0x5a: /* SecondaryBarrelSwitch */
> > > map_key_clear(BTN_STYLUS2);
> > > diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> > > index 65ea23be9677..a0b332518eaa 100644
> > > --- a/drivers/hid/hid-multitouch.c
> > > +++ b/drivers/hid/hid-multitouch.c
> > > @@ -974,6 +974,7 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
> > > field->application != HID_DG_TOUCHPAD &&
> > > field->application != HID_GD_KEYBOARD &&
> > > field->application != HID_GD_SYSTEM_CONTROL &&
> > > + field->application != HID_GD_SYSTEM_MULTIAXIS &&
> > > field->application != HID_CP_CONSUMER_CONTROL &&
> > > field->application != HID_GD_WIRELESS_RADIO_CTLS &&
> > > !(field->application == HID_VD_ASUS_CUSTOM_MEDIA_KEYS &&
> > > @@ -1003,6 +1004,14 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
> > > return 1;
> > > }
> > >
> > > + /*
> > > + * We do not want to export scantime on System MultiAxis
> > > + * for now
> > > + */
> > > + if (field->usage->hid == HID_DG_SCANTIME &&
> > > + field->application == HID_GD_SYSTEM_MULTIAXIS)
> > > + return -1;
> > > +
> > > /*
> > > * some egalax touchscreens have "application == HID_DG_TOUCHSCREEN"
> > > * for the stylus.
> > > @@ -1193,6 +1202,8 @@ static int mt_input_configured(struct hid_device *hdev, struct hid_input *hi)
> > > break;
> > > case HID_GD_MOUSE:
> > > suffix = "Mouse";
> > > + case HID_GD_SYSTEM_MULTIAXIS:
> > > + suffix = "MultiAxis";
> > > break;
> > > case HID_DG_STYLUS:
> > > suffix = "Pen";
> > > diff --git a/include/linux/hid.h b/include/linux/hid.h
> > > index d491027a7c22..f93ebbe2f23d 100644
> > > --- a/include/linux/hid.h
> > > +++ b/include/linux/hid.h
> > > @@ -189,6 +189,12 @@ struct hid_item {
> > > * http://www.usb.org/developers/hidpage/HUTRR40RadioHIDUsagesFinal.pdf
> > > */
> > > #define HID_GD_WIRELESS_RADIO_CTLS 0x0001000c
> > > +/*
> > > + * System Multi-Axis, see:
> > > + * http://www.usb.org/developers/hidpage/HUTRR62_-_Generic_Desktop_CA_for_System_Multi-Axis_Controllers.txt
> > > + */
> > > +#define HID_GD_SYSTEM_MULTIAXIS 0x0001000e
> > > +
> > > #define HID_GD_X 0x00010030
> > > #define HID_GD_Y 0x00010031
> > > #define HID_GD_Z 0x00010032
> > > diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h
> > > index 179891074b3c..f886499fdd4c 100644
> > > --- a/include/uapi/linux/input-event-codes.h
> > > +++ b/include/uapi/linux/input-event-codes.h
> > > @@ -406,6 +406,7 @@
> > > #define BTN_TOOL_MOUSE 0x146
> > > #define BTN_TOOL_LENS 0x147
> > > #define BTN_TOOL_QUINTTAP 0x148 /* Five fingers on trackpad */
> > > +#define BTN_TOOL_DIAL 0x149 /* System MultiAxis */
> > > #define BTN_TOUCH 0x14a
> > > #define BTN_STYLUS 0x14b
> > > #define BTN_STYLUS2 0x14c
> > > --
> > > 2.14.3
> > >
>
> --
> Dmitry