From: Christophe TORDEUX <christophe@xxxxxxxxxxx>
With kernel v4.6 and later, the Sentelic touchpad STL3888_C0 and
probably other Sentelic FSP touchpads are detected as a BYD touchpad and
lose multitouch features.
During the BYD handshake in the byd_detect function, the BYD driver
mistakenly interprets a standard PS/2 protocol status request answer
from the Sentelic touchpad as a successful handshake with a BYD
touchpad. This is clearly a bug of the BYD driver.
Description of the patch: In byd_detect function, remove positive
detection result based on standard PS/2 protocol status request answer.
Replace it with positive detection based on handshake answers as they
can be inferred from the BYD touchpad datasheets found on BYD website.
Signed-off-by: Christophe TORDEUX <christophe@xxxxxxxxxxx>
---
Resubmitting this patch because I got no feedback on my first
submission.
Fixes kernel bug 175421 which is impacting multiple users.
---
drivers/input/mouse/byd.c | 76
++++++++++++++++++++++++++++++++++++++---------
1 file changed, 62 insertions(+), 14 deletions(-)
diff --git a/drivers/input/mouse/byd.c b/drivers/input/mouse/byd.c
index b27aa63..b5acca0 100644
--- a/drivers/input/mouse/byd.c
+++ b/drivers/input/mouse/byd.c
@@ -35,6 +35,18 @@
* BYD pad constants
*/
+/* Handshake answer of BTP6034 */
+#define BYD_MODEL_BTP6034 0x00E801
+/* Handshake answer of BTP6740 */
+#define BYD_MODEL_BTP6740 0x001155
+/* Handshake answers of BTP8644, BTP10463 and BTP11484 */
+#define BYD_MODEL_BTP8644 0x011155
+
+/* Handshake SETRES byte of BTP6034 and BTP6740 */
+#define BYD_SHAKE_BYTE_A 0x00
+/* Handshake SETRES byte of BTP8644, BTP10463 and BTP11484 */
+#define BYD_SHAKE_BYTE_B 0x03
+
/*
* True device resolution is unknown, however experiments show the
* resolution is about 111 units/mm.
@@ -434,23 +446,59 @@ static void byd_disconnect(struct psmouse *psmouse)
}
}
+u32 byd_try_model(u32 model)
+{
+ size_t i;
+
+ u32 byd_model[] = {
+ BYD_MODEL_BTP6034,
+ BYD_MODEL_BTP6740,
+ BYD_MODEL_BTP8644
+ };
+
+ for (i=0; i < ARRAY_SIZE(byd_model); i++) {
+ if (model == byd_model[i])
+ return model;
+ }
+
+ return 0;
+}
+
int byd_detect(struct psmouse *psmouse, bool set_properties)
{
struct ps2dev *ps2dev = &psmouse->ps2dev;
- u8 param[4] = {0x03, 0x00, 0x00, 0x00};
-
- if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
- return -1;
- if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
- return -1;
- if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
- return -1;
- if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
- return -1;
- if (ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO))
- return -1;
-
- if (param[1] != 0x03 || param[2] != 0x64)
+ size_t i;
+
+ u8 byd_shbyte[] = {
+ BYD_SHAKE_BYTE_A,
+ BYD_SHAKE_BYTE_B
+ };
+
+ bool detect = false;
+ for (i=0; i < ARRAY_SIZE(byd_shbyte); i++) {
+ u32 model;
+ u8 param[4] = {byd_shbyte[i], 0x00, 0x00, 0x00};
+
+ if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+ return -1;
+ if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+ return -1;
+ if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+ return -1;
+ if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+ return -1;
+ if (ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO))
+ return -1;
+
+ model = param[2];
+ model += param[1] << 8;
+ model += param[0] << 16;
+ model = byd_try_model(model);
+ if (model)
+ detect = true;
+ }
+
+ if (!detect)
return -ENODEV;
psmouse_dbg(psmouse, "BYD touchpad detected\n");
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