On Monday 17 June 2019 20:05:55 Hui Wang wrote:
> On a latest Lenovo laptop, the trackpoint and 3 buttons below it
> don't work at all, when we move the trackpoint or press those 3
> buttons, the kernel will print out:
> "Rejected trackstick packet from non DualPoint device"
>
> This device is identified as alps touchpad but the packet has
> trackpoint format, so the alps.c drops the packet and prints out
> the message above.
>
> According to XiaoXiao's explanation, this device is named cs19 and
> is trackpoint-only device, its firmware is only for trackpoint, it
> is independent of touchpad and is a completely different device from
> DualPoint ones.
>
> To drive this device with mininal changes to the existing driver, we
> just let the alps driver not handle this device, then the trackpoint.c
> will be the driver of this device.
>
> With the trackpoint.c, this trackpoint and 3 buttons all work well,
> they have all features that the trackpoint should have, like
> scrolling-screen, drag-and-drop and frame-selection.
>
> Signed-off-by: XiaoXiao Liu <sliuuxiaonxiao@xxxxxxxxx>
> Signed-off-by: Hui Wang <hui.wang@xxxxxxxxxxxxx>
> ---
> Sorry, forgot to add "param[1] & 0x20" checking in the v3, please
> ignore the v3 patch.
> drivers/input/mouse/alps.c | 29 +++++++++++++++++++++++++++++
> 1 file changed, 29 insertions(+)
>
> diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c
> index 0a6f7ca883e7..6bed9eb16c2c 100644
> --- a/drivers/input/mouse/alps.c
> +++ b/drivers/input/mouse/alps.c
> @@ -24,6 +24,7 @@
>
> #include "psmouse.h"
> #include "alps.h"
> +#include "trackpoint.h"
>
> /*
> * Definitions for ALPS version 3 and 4 command mode protocol
> @@ -2864,6 +2865,23 @@ static const struct alps_protocol_info *alps_match_table(unsigned char *e7,
> return NULL;
> }
>
> +static bool alps_is_cs19_trackpoint(struct psmouse *psmouse)
> +{
> + u8 param[2] = { 0 };
> +
> + if (ps2_command(&psmouse->ps2dev,
> + param, MAKE_PS2_CMD(0, 2, TP_READ_ID)))
> + return false;
> +
> + if ((param[0] == TP_VARIANT_ALPS) && (param[1] & 0x20)) {
You should describe what does magic (param[1] & 0x20) check is doing.
Reading trakcpoint.c gives us assumption that param[1] is firmware id,
but why mask 0x20 is not explained.
> + psmouse_warn(psmouse,
> + "It is an ALPS trackpoint-only device (CS19), make sure the MOUSE_PS2_TRACKPOINT is enabled to drive it\n");
This will throw a warning for every CS19 device independently of kernel
configuration. You should not throw warning and spam users who compiled
kernel with trackpoint support.
Rather use something like this:
if (param[0] ...) {
if (IS_ENABLED(CONFIG_MOUSE_PS2_TRACKPOINT))
psmouse_dbg(psmouse, "ALPS CS19 trackpoint-only device detected, not using ALPS touchpad driver\n");
else
psmouse_warn(psmouse, "ALPS CS19 trackpoint-only device detected, but CONFIG_MOUSE_PS2_TRACKPOINT is not enabled, fallback to bare PS/2 mouse\n");
return true;
}
Just rephrase messages to not be too long and useful for user.
> + return true;
> + }
> +
> + return false;
> +}
> +
> static int alps_identify(struct psmouse *psmouse, struct alps_data *priv)
> {
> const struct alps_protocol_info *protocol;
> @@ -3164,6 +3182,17 @@ int alps_detect(struct psmouse *psmouse, bool set_properties)
> if (error)
> return error;
>
> + /*
> + * ALPS cs19 is a trackpoint-only device, it is completely independent
> + * of touchpad. So it is a different device from DualPoint ones, if it
> + * is identified as a cs19 trackpoint device, we return -EINVAL here and
> + * let trackpoint.c to drive this device.
> + * If ps2_command() fails here, we depend on the immediate followed
> + * psmouse_reset() to reset the device to normal state.
> + */
> + if (alps_is_cs19_trackpoint(psmouse))
> + return -EINVAL;
> +
> /*
> * Reset the device to make sure it is fully operational:
> * on some laptops, like certain Dell Latitudes, we may
--
Pali Rohár
pali.rohar@xxxxxxxxx
