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Date:   Sat, 02 Jan 2021 00:08:50 +0800
From:   "Jiaxun Yang" <jiaxun.yang@...goat.com>
To:     Barnabás Pőcze <pobrn@...tonmail.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



On Fri, Jan 1, 2021, at 10:20 PM, Barnabás Pőcze wrote:
> 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(...)`
> ?

Will fix.

> 
> 
> >  	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)`?

It is to prevent accidentally disable touchpad on machines that do have EC switch,
so it's intentional.

Thanks.

- Jiaxun

> 
> 
> 
> >  	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
>

-- 
- Jiaxun

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