Hi Christophe,
On Fri, Oct 07, 2016 at 12:41:48PM +0800, Christophe Tordeux wrote:
> 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>
What devices was this tested on? Do you have both BYD and Sentelic
devices?
I am really concerned about docs on BYD side as they seem to contradict
each other... I wonder how accurate they are.
Thanks.
>
> ---
> 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");
--
Dmitry
--
To unsubscribe from this list: send the line "unsubscribe linux-input" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
