On Thursday 13 June 2019 11:32:49 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>
> ---
> In the v2, I move the cs19 checking to alsp_detect(), and
> drop the param[1] checking. And because after executing
> alps_indetify(), the device is not in the command mode,
> i rewrite teh alsp_is_cs19_trackpoint() to add enter/exit_command_mode().
>
> drivers/input/mouse/alps.c | 32 ++++++++++++++++++++++++++++++++
> 1 file changed, 32 insertions(+)
>
> diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c
> index 0a6f7ca883e7..6f227e8ddd7e 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 +2865,28 @@ 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 (alps_enter_command_mode(psmouse))
> + return false;
Ufff... is this correct? Entering to command mode e.g. on rushmore
devices put ALPS touchpad into passthrough mode, when touchpad forwards
all packets from trackstick (connected to touchpad) directly to the
host.
I understood that ALPS trackpoint-only device do not have any touchpad,
so how is command mode suppose to work? What passthrough mean there?
Also does not it break e.g. ALPS rushmore devices?
I would suggest if you can provide architecture how this trackpoint-only
device is connected and which protocols it understand. Seems that there
are missing for us important details, like why is passthrough mode
needed and where it passthrough (there is a second device? which?).
> + if (ps2_command(&psmouse->ps2dev,
> + param, MAKE_PS2_CMD(0, 2, TP_READ_ID)))
> + return false;
So if ps2_command fails then device stay in passthrough mode forever.
And in past I was told by ALPS people that some ALPS rushmore devices
have a firmware bug that PS/2 reset command does not exit from
passthrough mode. So this code put some ALPS devices into fully
unusable and unresetable mode. And full machine power off is needed.
> + if (alps_exit_command_mode(psmouse))
> + return false;
> +
> + if (param[0] == TP_VARIANT_ALPS) {
> + psmouse_dbg(psmouse, "It is an ALPS trackpoint-only device (CS19)\n");
> + return true;
> + }
> +
> + return false;
> +}
> +
> static int alps_identify(struct psmouse *psmouse, struct alps_data *priv)
> {
> const struct alps_protocol_info *protocol;
> @@ -3164,6 +3187,15 @@ 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 (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
> --
> 2.17.1
>
--
Pali Rohár
pali.rohar@xxxxxxxxx
