linux-kernel - Re: [PATCH v2] Input: elantech - fix touchpad state on resume for Lenovo N24

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Date: Wed, 15 May 2024 10:29:58 -0500
From: Jonathan Denose <jdenose@...gle.com>
To: dmitry.torokhov@...il.com
Cc: gregkh@...uxfoundation.org, jefferymiller@...gle.com, 
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] Input: elantech - fix touchpad state on resume for
 Lenovo N24

On Fri, May 3, 2024 at 11:12 AM Jonathan Denose <jdenose@...gle.com> wrote:
>
> The Lenovo N24 on resume becomes stuck in a state where it
> sends incorrect packets, causing elantech_packet_check_v4 to fail.
> The only way for the device to resume sending the correct packets is for
> it to be disabled and then re-enabled.
>
> This change adds a dmi check to trigger this behavior on resume.
> Signed-off-by: Jonathan Denose <jdenose@...gle.com>
> ---
>
> Changes in v2:
> - change ps2_sendbyte() calls to ps2_command()
>
>  drivers/input/mouse/elantech.c | 33 +++++++++++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
>
> diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
> index 4e38229404b4b..18f26315cae25 100644
> --- a/drivers/input/mouse/elantech.c
> +++ b/drivers/input/mouse/elantech.c
> @@ -1476,6 +1476,23 @@ static void elantech_disconnect(struct psmouse *psmouse)
>         psmouse->private = NULL;
>  }
>
> +/*
> + * Some hw_version 4 models fail to properly activate absolute mode on
> + * resume without going through disable/enable cycle.
> + */
> +static const struct dmi_system_id elantech_needs_reenable[] = {
> +#if defined(CONFIG_DMI) && defined(CONFIG_X86)
> +       {
> +               /* Lenovo N24 */
> +               .matches = {
> +                       DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +                       DMI_MATCH(DMI_PRODUCT_NAME, "81AF"),
> +               },
> +       },
> +#endif
> +       { }
> +};
> +
>  /*
>   * Put the touchpad back into absolute mode when reconnecting
>   */
> @@ -1486,6 +1503,22 @@ static int elantech_reconnect(struct psmouse *psmouse)
>         if (elantech_detect(psmouse, 0))
>                 return -1;
>
> +       if (dmi_check_system(elantech_needs_reenable)) {
> +               int err;
> +
> +               err = ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_DISABLE);
> +
> +               if (err)
> +                       psmouse_warn(psmouse, "Failed to deactivate mouse on %s: %d\n",
> +                                       psmouse->ps2dev.serio->phys, err);
> +
> +               err = ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_ENABLE);
> +
> +               if (err)
> +                       psmouse_warn(psmouse, "Failed to reactivate mouse on %s: %d\n",
> +                                       psmouse->ps2dev.serio->phys, err);
> +       }
> +
>         if (elantech_set_absolute_mode(psmouse)) {
>                 psmouse_err(psmouse,
>                             "failed to put touchpad back into absolute mode.\n");
> --
> 2.45.0.rc1.225.g2a3ae87e7f-goog
>

Hello,

Is there anything else needed from me?
-- 
Jonathan