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Date:   Fri, 01 Jan 2021 14:20:15 +0000
From:   Barnabás Pőcze <pobrn@...tonmail.com>
To:     Jiaxun Yang <jiaxun.yang@...goat.com>
Cc:     "platform-driver-x86@...r.kernel.org" 
        <platform-driver-x86@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        Ike Panhc <ike.pan@...onical.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Mark Gross <mgross@...ux.intel.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] platform/x86: ideapad-laptop: Add has_touchpad_switch

Hi


2021. január 1., péntek 7:11 keltezéssel, Jiaxun Yang írta:

> Newer ideapads (e.g.: Yoga 14s, 720S 14) comes with I2C HID
> Touchpad and do not use EC to switch touchpad. Reading VPCCMD_R_TOUCHPAD
> will return zero thus touchpad may be blocked. Writing VPCCMD_W_TOUCHPAD
> may cause a spurious key press.
>
> Add has_touchpad_switch to workaround these machines.
>
> Signed-off-by: Jiaxun Yang <jiaxun.yang@...goat.com>
> Cc: stable@...r.kernel.org # 5.4+

Interestingly, the Lenovo Yoga 540-14IKB 80X8 has an HID-over-I2C touchpad,
and yet it can be controlled by reading/writing the appropriate EC registers.


> ---
>  drivers/platform/x86/ideapad-laptop.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/platform/x86/ideapad-laptop.c b/drivers/platform/x86/ideapad-laptop.c
> index 7598cd46cf60..b6a4db37d0fc 100644
> --- a/drivers/platform/x86/ideapad-laptop.c
> +++ b/drivers/platform/x86/ideapad-laptop.c
> @@ -92,6 +92,7 @@ struct ideapad_private {
>  	struct dentry *debug;
>  	unsigned long cfg;
>  	bool has_hw_rfkill_switch;
> +	bool has_touchpad_switch;
>  	const char *fnesc_guid;
>  };
>
> @@ -535,7 +536,9 @@ static umode_t ideapad_is_visible(struct kobject *kobj,
>  	} else if (attr == &dev_attr_fn_lock.attr) {
>  		supported = acpi_has_method(priv->adev->handle, "HALS") &&
>  			acpi_has_method(priv->adev->handle, "SALS");
> -	} else
> +	} else if (attr == &dev_attr_touchpad.attr)
> +		supported = priv->has_touchpad_switch;
> +	else
>  		supported = true;
>
>  	return supported ? attr->mode : 0;
> @@ -867,6 +870,9 @@ static void ideapad_sync_touchpad_state(struct ideapad_private *priv)
>  {
>  	unsigned long value;
>
> +	if (!priv->has_touchpad_switch)
> +		return;
> +
>  	/* Without reading from EC touchpad LED doesn't switch state */
>  	if (!read_ec_data(priv->adev->handle, VPCCMD_R_TOUCHPAD, &value)) {
>  		/* Some IdeaPads don't really turn off touchpad - they only
> @@ -989,6 +995,12 @@ static int ideapad_acpi_add(struct platform_device *pdev)
>  	priv->platform_device = pdev;
>  	priv->has_hw_rfkill_switch = dmi_check_system(hw_rfkill_list);
>
> +	/* Most ideapads with I2C HID don't use EC touchpad switch */
> +	if (acpi_dev_present("PNP0C50", NULL, -1))
> +		priv->has_touchpad_switch = false;
> +	else
> +		priv->has_touchpad_switch = true;
> +

`priv->has_touchpad_switch = !acpi_dev_present(...)`
?


>  	ret = ideapad_sysfs_init(priv);
>  	if (ret)
>  		return ret;
> @@ -1006,6 +1018,10 @@ static int ideapad_acpi_add(struct platform_device *pdev)
>  	if (!priv->has_hw_rfkill_switch)
>  		write_ec_cmd(priv->adev->handle, VPCCMD_W_RF, 1);
>
> +	/* The same for Touchpad */
> +	if (!priv->has_touchpad_switch)
> +		write_ec_cmd(priv->adev->handle, VPCCMD_W_TOUCHPAD, 1);
> +

Shouldn't it be the other way around: `if (priv->has_touchpad_switch)`?



>  	for (i = 0; i < IDEAPAD_RFKILL_DEV_NUM; i++)
>  		if (test_bit(ideapad_rfk_data[i].cfgbit, &priv->cfg))
>  			ideapad_register_rfkill(priv, i);
> --
> 2.30.0


Regards,
Barnabás Pőcze

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