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Subject: Re: [PATCH fixes v4] platform/x86: ideapad-laptop: Disable
 touchpad_switch for ELAN0634
To:     Jiaxun Yang <jiaxun.yang@flygoat.com>,
        platform-driver-x86@vger.kernel.org
Cc:     stable@vger.kernel.org, Ike Panhc <ike.pan@canonical.com>,
        Mark Gross <mgross@linux.intel.com>,
        linux-kernel@vger.kernel.org
References: <20210107144438.12605-1-jiaxun.yang@flygoat.com>
From:   Hans de Goede <hdegoede@redhat.com>
Message-ID: <dba9db5f-fa66-6003-382d-b35d5643d0d2@redhat.com>
Date:   Wed, 13 Jan 2021 10:24:45 +0100
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Hi,

On 1/7/21 3:44 PM, Jiaxun Yang wrote:
> Newer ideapads (e.g.: Yoga 14s, 720S 14) come with ELAN0634 touchpad do not
> use EC to switch touchpad.
> 
> Reading VPCCMD_R_TOUCHPAD will return zero thus touchpad may be blocked
> unexpectedly.
> 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@flygoat.com>
> Cc: stable@vger.kernel.org # 5.4+

Thank you for your patch, I've applied this patch to my review-hans 
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.

I will also cherry-pick this into the fixes branch and include
it in a future fixes pull-req for 5.11 .

Regards,

Hans


> --
> v2: Specify touchpad to ELAN0634
> v3: Stupid missing ! in v2
> v4: Correct acpi_dev_present usage (Hans)
> ---
>  drivers/platform/x86/ideapad-laptop.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/ideapad-laptop.c b/drivers/platform/x86/ideapad-laptop.c
> index 7598cd46cf60..5b81bafa5c16 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 +995,9 @@ 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 ELAN0634 touchpad don't use EC touchpad switch */
> +	priv->has_touchpad_switch = !acpi_dev_present("ELAN0634", NULL, -1);
> +
>  	ret = ideapad_sysfs_init(priv);
>  	if (ret)
>  		return ret;
> @@ -1006,6 +1015,10 @@ 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);
> +
>  	for (i = 0; i < IDEAPAD_RFKILL_DEV_NUM; i++)
>  		if (test_bit(ideapad_rfk_data[i].cfgbit, &priv->cfg))
>  			ideapad_register_rfkill(priv, i);
>