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Date: Sun, 8 May 2022 18:01:41 +0200
From: José Expósito <jose.exposito89@...il.com>
To: jikos@...nel.org
Cc: benjamin.tissoires@...hat.com, spbnick@...il.com,
linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
stefanberzl@...il.com, albertofanjul@...il.com,
José Expósito <jose.exposito89@...il.com>
Subject: [PATCH for-5.19/uclogic 2/7] HID: uclogic: Return raw parameters from v2 pen init
From: Nikolai Kondrashov <spbnick@...il.com>
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@...il.com>
Signed-off-by: José Expósito <jose.exposito89@...il.com>
---
drivers/hid/hid-uclogic-params.c | 92 ++++++++++++++++++++------------
1 file 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);
--
2.25.1
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