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Date:   Thu, 5 Jan 2023 18:38:46 +0100
From:   =?iso-8859-1?Q?Jos=E9_Exp=F3sito?= <jose.exposito89@gmail.com>
To:     Joshua Goins <josh@redstrate.com>
Cc:     linux-input@vger.kernel.org, kernel test robot <lkp@intel.com>,
        Dan Carpenter <error27@gmail.com>,
        Jiri Kosina <jikos@kernel.org>,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] HID: uclogic: Add support for XP-PEN Artist 22R Pro
Message-ID: <Y7cLJpgnP50JzHps@fedora>
References: <2068502.VLH7GnMWUR@adrastea>
 <20230102194911.56083-1-josh@redstrate.com>
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In-Reply-To: <20230102194911.56083-1-josh@redstrate.com>
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On Mon, Jan 02, 2023 at 02:49:10PM -0500, Joshua Goins wrote:
> Adds support for the XP-PEN Artist 22R Pro, including stylus, tablet frame
> and pen pressure.
> 
> The tablet has 20 buttons, but need to be remapped in order since the
> device reports invalid keycodes. Existing tablet functionality should
> not be inhibited, as BTN0-8 is still used.
> 
> New initialization functions are added since the device differs slightly
> from other UGEE v2 devices.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <error27@gmail.com>
> Reported-by: Jos? Exp?sito <jose.exposito89@gmail.com>
> Signed-off-by: Joshua Goins <josh@redstrate.com>
> ---
> v2 changes:
>   - rewrote initialization code to be more concise, and less error-prone, thanks
>   Dan Carpenter & Jos? Exp?sito for pointers!
>   - less struct duplication, it now uses compatiable UGEE v2 ones.
>   - uclogic_extra_input_mapping is now static, thanks Jos? again!
>   - straightened out dial transformation, now there's just the two cases and
>   they're decimal.
>   - fixed the patch formatting, it should be easier to apply now.
>   - rebased onto 6.2-rc2
> 
> I kept the new initialization functions seperate, please review and tell me if
> they are better suited being merged into their UGEE v2 counterparts (which would
> involve a lot of branching). I don't have another UGEE v2 tablet to test, so I
> won't be able to test for regressions for those devices myself, so I refrained
> from those changes in this patch.
> 
> Original message:
> I did not do the research for this hardware, or the original patch - that work
> has been done by Aren Villanueva. For some reason they decided not to merge
> it. My changes include remapping the stupid amount of tablet frame buttons,
> cleaning up the code to match kernel style, and other small stuff.
> 
> The tablet is (almost) fully functional even when uclogic doesn't handle it.
> Without initialization, the tablet has some sort of "basic driverless mode"
> that allows the tablet frame buttons to have some default keys associated with
> them (CTRL-S, CTRL-Z, that kind of stuff), but unfortunately the stylus pen
> semi-works. While pressure sensitivity works, only one stylus button functions
> correctly. Since the initialization process differs for Pro series tablets, the
> new function uclogic_params_init_ugee_xppen_pro had to be introduced. I also
> added USB HID IDs for this tablet too, but it's classified under the UGEE
> vendor ID.
> 
> One of the more strange things I had to do is figure out a way to remap the
> buttons since there are 20 of them in total, and of course there are more
> buttons than there are BTN constants defined for us. When running without
> uclogic, it starts at BTN_0, ends at BTN_8 and the tablet starts reporting
> nonsensical keycodes so just leaving it alone isn't an option. I'm testing
> this under a libinput system, which has a list of buttons it considers "tablet
> pad buttons" which are notably BTN_0, BTN_1, so on and some
> gamepad/joystick buttons. So I created a new array called
> uclogic_extra_input_mapping for 20 working inputs.
> 
> Another weird feature of this tablet is the second dial, which the original
> patchset introduced a new uclogic_frame param to handle since it seems it
> throws both dials values into one byte. The left wheel is considered EV_WHEEL
> and the other, EV_HWHEEL which seems fine to me. I also added the new param to
> the debug messages too.
> 
> 
>  drivers/hid/hid-ids.h            |   1 +
>  drivers/hid/hid-uclogic-core.c   |  66 +++++++++++-
>  drivers/hid/hid-uclogic-params.c | 180 +++++++++++++++++++++++++++++++
>  drivers/hid/hid-uclogic-params.h |   5 +
>  drivers/hid/hid-uclogic-rdesc.c  |  50 +++++++++
>  drivers/hid/hid-uclogic-rdesc.h  |   9 ++
>  6 files changed, 307 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
> index 82713ef3aaa6..81d04054229a 100644
> --- a/drivers/hid/hid-ids.h
> +++ b/drivers/hid/hid-ids.h
> @@ -1298,6 +1298,7 @@
>  #define USB_DEVICE_ID_UGEE_XPPEN_TABLET_DECO_L	0x0935
>  #define USB_DEVICE_ID_UGEE_XPPEN_TABLET_DECO_PRO_S	0x0909
>  #define USB_DEVICE_ID_UGEE_XPPEN_TABLET_STAR06	0x0078
> +#define USB_DEVICE_ID_UGEE_XPPEN_TABLET_22R_PRO	0x091b
>  #define USB_DEVICE_ID_UGEE_TABLET_G5		0x0074
>  #define USB_DEVICE_ID_UGEE_TABLET_EX07S		0x0071
>  #define USB_DEVICE_ID_UGEE_TABLET_RAINBOW_CV720	0x0055
> diff --git a/drivers/hid/hid-uclogic-core.c b/drivers/hid/hid-uclogic-core.c
> index 7fa6fe04f1b2..8d92e984f984 100644
> --- a/drivers/hid/hid-uclogic-core.c
> +++ b/drivers/hid/hid-uclogic-core.c
> @@ -81,6 +81,30 @@ static __u8 *uclogic_report_fixup(struct hid_device *hdev, __u8 *rdesc,
>  	return rdesc;
>  }
>  
> +/* Buttons considered valid tablet pad inputs. */
> +static const unsigned int uclogic_extra_input_mapping[] = {
> +	BTN_0,
> +	BTN_1,
> +	BTN_2,
> +	BTN_3,
> +	BTN_4,
> +	BTN_5,
> +	BTN_6,
> +	BTN_7,
> +	BTN_8,

I see this event codes in a test device mock in libinput, but I wonder
if we could/should use BTN_9 instead of skiping a few IDs here.

Honestly, I don't now what should be the right approach in this case,
let's see if someone else comments on this topic.

> +	BTN_RIGHT,
> +	BTN_MIDDLE,
> +	BTN_SIDE,
> +	BTN_EXTRA,
> +	BTN_FORWARD,
> +	BTN_BACK,
> +	BTN_B,
> +	BTN_A,
> +	BTN_BASE,
> +	BTN_BASE2,
> +	BTN_X
> +};
> +
>  static int uclogic_input_mapping(struct hid_device *hdev,
>  				 struct hid_input *hi,
>  				 struct hid_field *field,
> @@ -91,9 +115,27 @@ static int uclogic_input_mapping(struct hid_device *hdev,
>  	struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
>  	struct uclogic_params *params = &drvdata->params;
>  
> -	/* Discard invalid pen usages */
> -	if (params->pen.usage_invalid && (field->application == HID_DG_PEN))
> -		return -1;
> +	if (field->application == HID_GD_KEYPAD) {
> +		/*
> +		 * Remap input buttons to sensible ones that are not invalid.
> +		 * This only affects previous behavior for devices with more than ten or so buttons.
> +		 */
> +		const int key = (usage->hid & HID_USAGE) - 1;
> +
> +		if (key > 0 && key < ARRAY_SIZE(uclogic_extra_input_mapping)) {
> +			hid_map_usage(hi,
> +				      usage,
> +				      bit,
> +				      max,
> +				      EV_KEY,
> +				      uclogic_extra_input_mapping[key]);
> +			return 1;
> +		}
> +	} else if (field->application == HID_DG_PEN) {
> +		/* Discard invalid pen usages */
> +		if (params->pen.usage_invalid)
> +			return -1;
> +	}
>  
>  	/* Let hid-core decide what to do */
>  	return 0;
> @@ -403,8 +445,22 @@ static int uclogic_raw_event_frame(
>  
>  	/* If need to, and can, transform the bitmap dial reports */
>  	if (frame->bitmap_dial_byte > 0 && frame->bitmap_dial_byte < size) {
> -		if (data[frame->bitmap_dial_byte] == 2)
> +		switch (data[frame->bitmap_dial_byte]) {
> +		case 2:
>  			data[frame->bitmap_dial_byte] = -1;
> +			break;
> +
> +		/* Everything below here is for tablets that shove multiple dials into 1 byte */
> +		case 16:
> +			data[frame->bitmap_dial_byte] = 0;
> +			data[frame->bitmap_second_dial_destination_byte] = 1;
> +			break;
> +
> +		case 32:
> +			data[frame->bitmap_dial_byte] = 0;
> +			data[frame->bitmap_second_dial_destination_byte] = -1;
> +			break;
> +		}
>  	}
>  
>  	return 0;
> @@ -531,6 +587,8 @@ static const struct hid_device_id uclogic_devices[] = {
>  				USB_DEVICE_ID_UGEE_XPPEN_TABLET_DECO_PRO_S) },
>  	{ HID_USB_DEVICE(USB_VENDOR_ID_UGEE,
>  				USB_DEVICE_ID_UGEE_XPPEN_TABLET_STAR06) },
> +	{ HID_USB_DEVICE(USB_VENDOR_ID_UGEE,
> +				USB_DEVICE_ID_UGEE_XPPEN_TABLET_22R_PRO) },
>  	{ }
>  };
>  MODULE_DEVICE_TABLE(hid, uclogic_devices);
> diff --git a/drivers/hid/hid-uclogic-params.c b/drivers/hid/hid-uclogic-params.c
> index cd1233d7e253..d53c464a1b15 100644
> --- a/drivers/hid/hid-uclogic-params.c
> +++ b/drivers/hid/hid-uclogic-params.c
> @@ -103,6 +103,8 @@ static void uclogic_params_frame_hid_dbg(
>  		frame->touch_flip_at);
>  	hid_dbg(hdev, "\t\t.bitmap_dial_byte = %u\n",
>  		frame->bitmap_dial_byte);
> +	hid_dbg(hdev, "\t\t.bitmap_second_dial_destination_byte = %u\n",
> +			frame->bitmap_second_dial_destination_byte);
>  }
>  
>  /**
> @@ -1418,6 +1420,174 @@ static int uclogic_params_ugee_v2_init(struct uclogic_params *params,
>  	return rc;
>  }
>  
> +/**
> + * uclogic_params_parse_ugee_xppen_pro_desc - parse the string descriptor
> + * containing pen and frame parameters returned by XP-PEN Pro devices.
> + *
> + * @str_desc:		String descriptor, cannot be NULL.
> + * @str_desc_size:	Size of the string descriptor.
> + * @desc_params:	Output description params list.
> + * @desc_params_size:	Size of the output description params list.
> + *
> + * Returns:
> + *	Zero, if successful. A negative errno code on error.
> + */
> +static int uclogic_params_parse_ugee_xppen_pro_desc(const __u8 *str_desc,

I think that you could use uclogic_params_parse_ugee_v2_desc() and
change the number of buttons in the template afterwards. It'd avoid
some code duplication.

> +					     size_t str_desc_size,
> +					     s32 *desc_params,
> +					     size_t desc_params_size)
> +{
> +	s32 pen_x_lm, pen_y_lm;
> +	s32 pen_x_pm, pen_y_pm;
> +	s32 pen_pressure_lm;
> +	s32 resolution;
> +
> +	/* Minimum descriptor length required, maximum seen so far is 14 */
> +	const int min_str_desc_size = 12;
> +
> +	if (!str_desc || str_desc_size < min_str_desc_size)
> +		return -EINVAL;
> +
> +	if (desc_params_size != UCLOGIC_RDESC_PH_ID_NUM)
> +		return -EINVAL;
> +
> +	pen_x_lm = get_unaligned_le16(str_desc + 2);
> +	pen_y_lm = get_unaligned_le16(str_desc + 4);
> +	pen_pressure_lm = get_unaligned_le16(str_desc + 8);
> +
> +	resolution = get_unaligned_le16(str_desc + 10);
> +	if (resolution == 0) {
> +		pen_x_pm = 0;
> +		pen_y_pm = 0;
> +	} else {
> +		pen_x_pm = pen_x_lm * 1000 / resolution;
> +		pen_y_pm = pen_y_lm * 1000 / resolution;
> +	}
> +
> +	desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_LM] = pen_x_lm;
> +	desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_PM] = pen_x_pm;
> +	desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_LM] = pen_y_lm;
> +	desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_PM] = pen_y_pm;
> +	desc_params[UCLOGIC_RDESC_PEN_PH_ID_PRESSURE_LM] = pen_pressure_lm;
> +
> +	return 0;
> +}
> +
> +/*
> + * uclogic_params_init_ugee_xppen_pro() - Initializes a UGEE XP-Pen Pro tablet device.
> + *
> + * @hdev:	The HID device of the tablet interface to initialize and get
> + *		parameters from. Cannot be NULL.
> + * @params:	Parameters to fill in (to be cleaned with
> + *		uclogic_params_cleanup()). Not modified in case of error.
> + *		Cannot be NULL.
> + *
> + * Returns:
> + *	Zero, if successful. A negative errno code on error.
> + */
> +static int uclogic_params_init_ugee_xppen_pro(struct uclogic_params *params,

There are some XP-Pen PRO devices handled by the other init function.
Maybe we could rename this function to something more specific to your
device.

> +					      struct hid_device *hdev,
> +					      const u8 rdesc_frame_arr[],
> +					      const size_t rdesc_frame_size)
> +{
> +	int rc = 0;
> +	struct usb_interface *iface;
> +	__u8 bInterfaceNumber;
> +	const int str_desc_len = 12;
> +	u8 *str_desc = NULL;
> +	__u8 *rdesc_pen = NULL;
> +	s32 desc_params[UCLOGIC_RDESC_PH_ID_NUM];
> +	/* The resulting parameters (noop) */
> +	struct uclogic_params p = {0, };
> +
> +	if (!hdev || !params) {
> +		rc = -EINVAL;
> +		goto cleanup;
> +	}
> +
> +	iface = to_usb_interface(hdev->dev.parent);
> +	bInterfaceNumber = iface->cur_altsetting->desc.bInterfaceNumber;
> +
> +	/* Ignore non-pen interfaces */
> +	if (bInterfaceNumber != 2) {
> +		uclogic_params_init_invalid(&p);
> +		goto output;
> +	}
> +
> +	/*
> +	 * Initialize the interface by sending magic data.
> +	 * This magic data is the same as other UGEE v2 tablets.
> +	 */
> +	rc = uclogic_probe_interface(hdev,
> +				     uclogic_ugee_v2_probe_arr,
> +				     uclogic_ugee_v2_probe_size,
> +				     0x03);

You can use "uclogic_ugee_v2_probe_endpoint" here.

> +	if (rc) {
> +		uclogic_params_init_invalid(&p);
> +		goto output;
> +	}
> +
> +	/**
> +	 * Read the string descriptor containing pen and frame parameters.
> +	 * These are slightly different than typical UGEE v2 devices.
> +	 */
> +	rc = uclogic_params_get_str_desc(&str_desc, hdev, 100, str_desc_len);
> +	if (rc != str_desc_len) {
> +		hid_err(hdev, "failed retrieving pen and frame parameters: %d\n", rc);
> +		uclogic_params_init_invalid(&p);
> +		goto output;
> +	}
> +
> +	rc = uclogic_params_parse_ugee_xppen_pro_desc(str_desc, str_desc_len,
> +						      desc_params,
> +						      ARRAY_SIZE(desc_params));
> +	if (rc)
> +		goto cleanup;
> +
> +	kfree(str_desc);
> +	str_desc = NULL;
> +
> +	/* Initialize the pen interface */
> +	rdesc_pen = uclogic_rdesc_template_apply(
> +				uclogic_rdesc_ugee_v2_pen_template_arr,
> +				uclogic_rdesc_ugee_v2_pen_template_size,
> +				desc_params, ARRAY_SIZE(desc_params));
> +	if (!rdesc_pen) {
> +		rc = -ENOMEM;
> +		goto cleanup;
> +	}
> +
> +	p.pen.desc_ptr = rdesc_pen;
> +	p.pen.desc_size = uclogic_rdesc_ugee_v2_pen_template_size;
> +	p.pen.id = 0x02;
> +	p.pen.subreport_list[0].value = 0xf0;
> +	p.pen.subreport_list[0].id = UCLOGIC_RDESC_V1_FRAME_ID;
> +
> +	/* Initialize the frame interface */
> +	rc = uclogic_params_frame_init_with_desc(
> +		&p.frame_list[0],
> +		rdesc_frame_arr,
> +		rdesc_frame_size,
> +		UCLOGIC_RDESC_V1_FRAME_ID);
> +	if (rc < 0) {
> +		hid_err(hdev, "initializing frame params failed: %d\n", rc);
> +		goto output;
> +	}
> +
> +	p.frame_list[0].bitmap_dial_byte = 7;
> +	p.frame_list[0].bitmap_second_dial_destination_byte = 8;
> +
> +output:
> +	/* Output parameters */
> +	memcpy(params, &p, sizeof(*params));
> +	memset(&p, 0, sizeof(p));
> +	rc = 0;
> +cleanup:
> +	kfree(str_desc);
> +	uclogic_params_cleanup(&p);
> +	return rc;
> +}
> +
>  /**
>   * uclogic_params_init() - initialize a tablet interface and discover its
>   * parameters.
> @@ -1728,6 +1898,16 @@ int uclogic_params_init(struct uclogic_params *params,
>  			uclogic_params_init_invalid(&p);
>  		}
>  
> +		break;
> +	case VID_PID(USB_VENDOR_ID_UGEE,
> +			USB_DEVICE_ID_UGEE_XPPEN_TABLET_22R_PRO):
> +		rc = uclogic_params_init_ugee_xppen_pro(&p,
> +			hdev,
> +			uclogic_rdesc_xppen_artist_22r_pro_frame_arr,
> +			uclogic_rdesc_xppen_artist_22r_pro_frame_size);
> +		if (rc != 0)
> +			goto cleanup;
> +
>  		break;
>  	}
>  
> diff --git a/drivers/hid/hid-uclogic-params.h b/drivers/hid/hid-uclogic-params.h
> index a97477c02ff8..6621a75a4b1a 100644
> --- a/drivers/hid/hid-uclogic-params.h
> +++ b/drivers/hid/hid-uclogic-params.h
> @@ -171,6 +171,11 @@ struct uclogic_params_frame {
>  	 * counterclockwise, as opposed to the normal 1 and -1.
>  	 */
>  	unsigned int bitmap_dial_byte;
> +	/*
> +	 * Destination offset for the second bitmap dial byte, if the tablet
> +	 * supports a second dial at all.
> +	 */
> +	unsigned int bitmap_second_dial_destination_byte;
>  };
>  
>  /*
> diff --git a/drivers/hid/hid-uclogic-rdesc.c b/drivers/hid/hid-uclogic-rdesc.c
> index fb40775f5f5b..86293ae8c995 100644
> --- a/drivers/hid/hid-uclogic-rdesc.c
> +++ b/drivers/hid/hid-uclogic-rdesc.c
> @@ -859,6 +859,12 @@ const __u8 uclogic_rdesc_v2_frame_dial_arr[] = {
>  const size_t uclogic_rdesc_v2_frame_dial_size =
>  			sizeof(uclogic_rdesc_v2_frame_dial_arr);
>  
> +const __u8 uclogic_ugee_v2_probe_arr[] = {
> +	0x02, 0xb0, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
> +};
> +const size_t uclogic_ugee_v2_probe_size = sizeof(uclogic_ugee_v2_probe_arr);
> +const int uclogic_ugee_v2_probe_endpoint = 0x03;
> +
>  /* Fixed report descriptor template for UGEE v2 pen reports */
>  const __u8 uclogic_rdesc_ugee_v2_pen_template_arr[] = {
>  	0x05, 0x0d,         /*  Usage Page (Digitizers),                */
> @@ -1185,6 +1191,50 @@ const __u8 uclogic_rdesc_xppen_deco01_frame_arr[] = {
>  const size_t uclogic_rdesc_xppen_deco01_frame_size =
>  			sizeof(uclogic_rdesc_xppen_deco01_frame_arr);
>  
> +/* Fixed report descriptor for XP-Pen Arist 22R Pro frame */
> +const __u8 uclogic_rdesc_xppen_artist_22r_pro_frame_arr[] = {

User-space lacks support for dials, but, with this descriptor, would it
be possible to differenciate between the 2 dials to, for example,
assign them different actions? Or would them be exposed as the same
dial?

I have no idea how would user-space see this, but it'd interesting to
see how libinput handles it.

> +	0x05, 0x01,         /*  Usage Page (Desktop),                       */
> +	0x09, 0x07,         /*  Usage (Keypad),                             */
> +	0xA1, 0x01,         /*  Collection (Application),                   */
> +	0x85, UCLOGIC_RDESC_V1_FRAME_ID,
> +	/*      Report ID (Virtual report),             */
> +	0x05, 0x0D,         /*     Usage Page (Digitizer),                  */
> +	0x09, 0x39,         /*      Usage (Tablet Function Keys),           */
> +	0xA0,               /*      Collection (Physical),                  */
> +	0x14,               /*          Logical Minimum (0),                */
> +	0x25, 0x01,         /*          Logical Maximum (1),                */
> +	0x75, 0x01,         /*          Report Size (1),                    */
> +	0x95, 0x08,         /*          Report Count (8),                   */
> +	0x81, 0x01,         /*          Input (Constant),                   */
> +	0x05, 0x09,         /*          Usage Page (Button),                */
> +	0x19, 0x01,         /*          Usage Minimum (01h),                */
> +	0x29, 0x14,         /*          Usage Maximum (14h),                */
> +	0x95, 0x14,         /*          Report Count (20),                  */
> +	0x81, 0x02,         /*          Input (Variable),                   */
> +	0x95, 0x14,         /*          Report Count (20),                  */
> +	0x81, 0x01,         /*          Input (Constant),                   */
> +	0x05, 0x01,         /*          Usage Page (Desktop),               */
> +	0x09, 0x38,         /*          Usage (Wheel),                      */
> +	0x75, 0x08,         /*          Report Size (8),                    */
> +	0x95, 0x01,         /*          Report Count (1),                   */
> +	0x15, 0xFF,         /*          Logical Minimum (-1),               */
> +	0x25, 0x08,         /*          Logical Maximum (8),                */
> +	0x81, 0x06,         /*          Input (Variable, Relative),         */
> +	0x05, 0x0C,         /*          Usage Page (Consumer Devices),      */
> +	0x0A, 0x38, 0x02,   /*          Usage (AC PAN),                     */
> +	0x95, 0x01,         /*          Report Count (1),                   */
> +	0x81, 0x06,         /*          Input (Variable, Relative),         */
> +	0x26, 0xFF, 0x00,   /*          Logical Maximum (255),              */
> +	0x75, 0x08,         /*          Report Size (8),                    */
> +	0x95, 0x01,         /*          Report Count (1),                   */
> +	0x81, 0x02,         /*          Input (Variable),                   */
> +	0xC0,               /*      End Collection                          */
> +	0xC0,               /*  End Collection                              */
> +};
> +
> +const size_t uclogic_rdesc_xppen_artist_22r_pro_frame_size =
> +				sizeof(uclogic_rdesc_xppen_artist_22r_pro_frame_arr);
> +
>  /**
>   * uclogic_rdesc_template_apply() - apply report descriptor parameters to a
>   * report descriptor template, creating a report descriptor. Copies the
> diff --git a/drivers/hid/hid-uclogic-rdesc.h b/drivers/hid/hid-uclogic-rdesc.h
> index a1f78c07293f..c3cb2c75dda5 100644
> --- a/drivers/hid/hid-uclogic-rdesc.h
> +++ b/drivers/hid/hid-uclogic-rdesc.h
> @@ -164,6 +164,11 @@ extern const size_t uclogic_rdesc_v2_frame_dial_size;
>  /* Report ID for tweaked UGEE v2 battery reports */
>  #define UCLOGIC_RDESC_UGEE_V2_BATTERY_ID 0xba
>  
> +/* Magic data expected by UGEEv2 devices on probe */
> +extern const __u8 uclogic_ugee_v2_probe_arr[];
> +extern const size_t uclogic_ugee_v2_probe_size;
> +extern const int uclogic_ugee_v2_probe_endpoint;
> +

You can cherry-pick my patch refactoring this variables and send it as
part of your series. I think that it might help maintainers with the
merge and it'd also fix the problem reported by the test robot.

>  /* Fixed report descriptor template for UGEE v2 pen reports */
>  extern const __u8 uclogic_rdesc_ugee_v2_pen_template_arr[];
>  extern const size_t uclogic_rdesc_ugee_v2_pen_template_size;
> @@ -205,4 +210,8 @@ extern const size_t uclogic_rdesc_ugee_g5_frame_size;
>  /* Least-significant bit of Ugee G5 frame rotary encoder state */
>  #define UCLOGIC_RDESC_UGEE_G5_FRAME_RE_LSB 38
>  
> +/* Fixed report descriptor for XP-Pen Arist 22R Pro frame */
> +extern const __u8 uclogic_rdesc_xppen_artist_22r_pro_frame_arr[];
> +extern const size_t uclogic_rdesc_xppen_artist_22r_pro_frame_size;
> +
>  #endif /* _HID_UCLOGIC_RDESC_H */
> 
> base-commit: 88603b6dc419445847923fcb7fe5080067a30f98
> -- 
> 2.38.2
>