diff options
Diffstat (limited to 'drivers/hid')
| -rw-r--r-- | drivers/hid/hid-uclogic-params.c | 92 |
1 files changed, 58 insertions, 34 deletions
diff --git a/drivers/hid/hid-uclogic-params.c b/drivers/hid/hid-uclogic-params.c index 1d9168cc7dc0..91379d7cd33e 100644 --- a/drivers/hid/hid-uclogic-params.c +++ b/drivers/hid/hid-uclogic-params.c @@ -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); |