linux-kernel - Re: [PATCH] Add a quirk for the Dell XPS 13 (2015) when in PS/2 mode.

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Date:	Thu, 19 Feb 2015 09:16:39 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Mario Limonciello <mario_limonciello@...l.com>
Cc:	LKML <linux-kernel@...r.kernel.org>, linux-input@...r.kernel.org
Subject: Re: [PATCH] Add a quirk for the Dell XPS 13 (2015) when in PS/2 mode.

Hi Mario,

On Wed, Feb 18, 2015 at 07:43:00PM -0600, Mario Limonciello wrote:
> When the touchpad for the Dell XPS 13 is running in PS/2 mode the
> EC has a tendency to glitch causing the driver to receive bad data.
> This doesn't affect the usage of the touchpad until enough bad data
> is received that causes the driver to reset and "freeze".
> 

What kind of glitch is this? Is there a certain pattern to it? Even if we do
not reset the mouse the logs will be full of error messages.

Thanks.

> Signed-off-by: Mario Limonciello <mario_limonciello@...l.com>
> ---
>  drivers/input/mouse/synaptics.c | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
> index 7e705ee..4dc456c 100644
> --- a/drivers/input/mouse/synaptics.c
> +++ b/drivers/input/mouse/synaptics.c
> @@ -1244,6 +1244,21 @@ static int synaptics_reconnect(struct psmouse *psmouse)
>  	return 0;
>  }
>  
> +static bool dell_ec_glitch;
> +
> +static const struct dmi_system_id dell_dmi_table[] __initconst = {
> +#if defined(CONFIG_DMI) && defined(CONFIG_X86)
> +	{
> +		/* XPS 13 (2015) */
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "XPS 13 9343"),
> +		},
> +	},
> +	{ }
> +#endif
> +};
> +
>  static bool impaired_toshiba_kbc;
>  
>  static const struct dmi_system_id toshiba_dmi_table[] __initconst = {
> @@ -1334,6 +1349,8 @@ void __init synaptics_module_init(void)
>  	 * so we have to resort to checking DMI.
>  	 */
>  	is_forcepad = dmi_check_system(forcepad_dmi_table);
> +	dell_ec_glitch = dmi_check_system(dell_dmi_table);
> +
>  }
>  
>  static int __synaptics_init(struct psmouse *psmouse, bool absolute_mode)
> @@ -1426,6 +1443,17 @@ static int __synaptics_init(struct psmouse *psmouse, bool absolute_mode)
>  		psmouse->rate = 40;
>  	}
>  
> +	/*
> +	 * Some Dell touchpads have a problem where the EC will glitch causing
> +	 * bad packets that are otherwise harmless unless they cause psmouse
> +	 * to reset.
> +	 */
> +	if (psmouse->resetafter > 0 && dell_ec_glitch) {
> +		psmouse_info(psmouse, "Dell %s detected, disabling tpad reset.\n",
> +			dmi_get_system_info(DMI_PRODUCT_NAME));
> +		psmouse->resetafter = 0;
> +	}
> +
>  	if (!priv->absolute_mode && SYN_ID_DISGEST_SUPPORTED(priv->identity)) {
>  		err = device_create_file(&psmouse->ps2dev.serio->dev,
>  					 &psmouse_attr_disable_gesture.dattr);
> -- 
> 1.9.1
> 

-- 
Dmitry
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