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HID: uclogic: Return raw parameters from v2 pen init

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Return the raw parameters buffer from uclogic_params_pen_init_v2(), if
requested, as a way to identify the tablet.

Signed-off-by: Nikolai Kondrashov <spbnick@gmail.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Nikolai Kondrashov 2022-05-08 18:01:41 +02:00 committed by Jiri Kosina
parent a228809fa6
commit 945d5dd5a5
1 changed files with 58 additions and 34 deletions
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92
drivers/hid/hid-uclogic-params.c
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@ -338,28 +338,45 @@ static s32 uclogic_params_get_le24(const void *p)
* uclogic_params_pen_init_v2() - initialize tablet interface pen
* input and retrieve its parameters from the device, using v2 protocol.
*
* @pen: Pointer to the pen parameters to initialize (to be
* cleaned up with uclogic_params_pen_cleanup()). Not modified in
* case of error, or if parameters are not found. Cannot be NULL.
* @pfound: Location for a flag which is set to true if the parameters
* were found, and to false if not (e.g. device was
* incompatible). Not modified in case of error. Cannot be NULL.
* @hdev: The HID device of the tablet interface to initialize and get
* parameters from. Cannot be NULL.
* @pen: Pointer to the pen parameters to initialize (to be
* cleaned up with uclogic_params_pen_cleanup()). Not
* modified in case of error, or if parameters are not
* found. Cannot be NULL.
* @pfound: Location for a flag which is set to true if the
* parameters were found, and to false if not (e.g.
* device was incompatible). Not modified in case of
* error. Cannot be NULL.
* @pparams_ptr: Location for a kmalloc'ed pointer to the retrieved raw
* parameters, which could be used to identify the tablet
* to some extent. Should be freed with kfree after use.
* NULL, if not needed. Not modified in case of error.
* Only set if *pfound is set to true.
* @pparams_len: Location for the length of the retrieved raw
* parameters. NULL, if not needed. Not modified in case
* of error. Only set if *pfound is set to true.
* @hdev: The HID device of the tablet interface to initialize
* and get parameters from. Cannot be NULL.
*
* Returns:
* Zero, if successful. A negative errno code on error.
*/
static int uclogic_params_pen_init_v2(struct uclogic_params_pen *pen,
bool *pfound,
__u8 **pparams_ptr,
size_t *pparams_len,
struct hid_device *hdev)
{
int rc;
bool found = false;
/* Buffer for (part of) the string descriptor */
/* Buffer for (part of) the parameter string descriptor */
__u8 *buf = NULL;
/* Descriptor length required */
const int len = 18;
/* Parameter string descriptor required length */
const int params_len_min = 18;
/* Parameter string descriptor accepted length */
const int params_len_max = 32;
/* Parameter string descriptor received length */
int params_len;
size_t i;
s32 resolution;
/* Pen report descriptor template parameters */
s32 desc_params[UCLOGIC_RDESC_PEN_PH_ID_NUM];
@ -377,7 +394,7 @@ static int uclogic_params_pen_init_v2(struct uclogic_params_pen *pen,
* the Windows driver traffic.
* NOTE: This enables fully-functional tablet mode.
*/
rc = uclogic_params_get_str_desc(&buf, hdev, 200, len);
rc = uclogic_params_get_str_desc(&buf, hdev, 200, params_len_max);
if (rc == -EPIPE) {
hid_dbg(hdev,
"string descriptor with pen parameters not found, assuming not compatible\n");
@ -385,27 +402,28 @@ static int uclogic_params_pen_init_v2(struct uclogic_params_pen *pen,
} else if (rc < 0) {
hid_err(hdev, "failed retrieving pen parameters: %d\n", rc);
goto cleanup;
} else if (rc != len) {
} else if (rc < params_len_min) {
hid_dbg(hdev,
"string descriptor with pen parameters has invalid length (got %d, expected %d), assuming not compatible\n",
rc, len);
"string descriptor with pen parameters is too short (got %d, expected at least %d), assuming not compatible\n",
rc, params_len_min);
goto finish;
}
params_len = rc;
/*
* Check it's not just a catch-all UTF-16LE-encoded ASCII
* string (such as the model name) some tablets put into all
* unknown string descriptors.
*/
for (i = 2;
i < params_len &&
(buf[i] >= 0x20 && buf[i] < 0x7f && buf[i + 1] == 0);
i += 2);
if (i >= params_len) {
hid_dbg(hdev,
"string descriptor with pen parameters seems to contain only text, assuming not compatible\n");
goto finish;
} else {
size_t i;
/*
* Check it's not just a catch-all UTF-16LE-encoded ASCII
* string (such as the model name) some tablets put into all
* unknown string descriptors.
*/
for (i = 2;
i < len &&
(buf[i] >= 0x20 && buf[i] < 0x7f && buf[i + 1] == 0);
i += 2);
if (i >= len) {
hid_dbg(hdev,
"string descriptor with pen parameters seems to contain only text, assuming not compatible\n");
goto finish;
}
}
/*
@ -429,8 +447,6 @@ static int uclogic_params_pen_init_v2(struct uclogic_params_pen *pen,
desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_LM] * 1000 /
resolution;
}
kfree(buf);
buf = NULL;
/*
* Generate pen report descriptor
@ -456,6 +472,13 @@ static int uclogic_params_pen_init_v2(struct uclogic_params_pen *pen,
pen->fragmented_hires = true;
pen->tilt_y_flipped = true;
found = true;
if (pparams_ptr != NULL) {
*pparams_ptr = buf;
buf = NULL;
}
if (pparams_len != NULL)
*pparams_len = params_len;
finish:
*pfound = found;
rc = 0;
@ -828,7 +851,8 @@ static int uclogic_params_huion_init(struct uclogic_params *params,
"transition firmware detected, not probing pen v2 parameters\n");
} else {
/* Try to probe v2 pen parameters */
rc = uclogic_params_pen_init_v2(&p.pen, &found, hdev);
rc = uclogic_params_pen_init_v2(&p.pen, &found,
NULL, NULL, hdev);
if (rc != 0) {
hid_err(hdev,
"failed probing pen v2 parameters: %d\n", rc);