linux-kernel - Re: [PATCH 45/51] Input: atmel_mxt_ts - Release touch state during suspend

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 18 Jul 2013 19:29:53 +0200
From:	rydberg@...omail.se
To:	Nick Dyer <nick.dyer@...ev.co.uk>
Cc:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Daniel Kurtz <djkurtz@...omium.org>,
	Joonyoung Shim <jy0922.shim@...sung.com>,
	Alan Bowens <Alan.Bowens@...el.com>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
	Peter Meerwald <pmeerw@...erw.net>,
	Benson Leung <bleung@...omium.org>,
	Olof Johansson <olofj@...omium.org>
Subject: Re: [PATCH 45/51] Input: atmel_mxt_ts - Release touch state during
 suspend

On Thu, Jun 27, 2013 at 01:49:20PM +0100, Nick Dyer wrote:
> If fingers are down as the MXT chip goes into suspend it does not send a lift
> message. In addition, it may not complete its final measurement cycle
> immediately, which means touch messages may be received by the interrupt
> handler after mxt_stop() has completed.

How long is the window of possible stray interrupts? Could this be
done with a small delay instead of keeping track of the suspend state?

> So:
> - disable irq during suspend
> - flush any messages created after suspend
> - tell app layer that slots were released at suspend
> 
> Signed-off-by: Nick Dyer <nick.dyer@...ev.co.uk>
> Acked-by: Benson Leung <bleung@...omium.org>
> ---
>  drivers/input/touchscreen/atmel_mxt_ts.c |   46 ++++++++++++++++++++++++++++++
>  1 file changed, 46 insertions(+)
> 
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> index ceb090a..b4ecd1d 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -249,6 +249,9 @@ struct mxt_data {
>  
>  	/* Enable reporting of input events */
>  	bool enable_reporting;
> +
> +	/* Indicates whether device is in suspend */
> +	bool suspended;
>  };
>  
>  static inline size_t mxt_obj_size(const struct mxt_object *obj)
> @@ -2025,6 +2028,11 @@ static int mxt_load_fw(struct device *dev, const char *fn)
>  	if (ret)
>  		goto release_firmware;
>  
> +	if (data->suspended) {
> +		enable_irq(data->irq);
> +		data->suspended = false;
> +	}
> +
>  	if (!data->in_bootloader) {
>  		/* Change to the bootloader mode */
>  		data->in_bootloader = true;
> @@ -2137,6 +2145,8 @@ static ssize_t mxt_update_fw_store(struct device *dev,
>  	} else {
>  		dev_info(dev, "The firmware update succeeded\n");
>  
> +		data->suspended = false;
> +
>  		error = mxt_initialize(data);
>  		if (error)
>  			return error;
> @@ -2162,17 +2172,53 @@ static const struct attribute_group mxt_attr_group = {
>  	.attrs = mxt_attrs,
>  };
>  
> +static void mxt_reset_slots(struct mxt_data *data)
> +{
> +	struct input_dev *input_dev = data->input_dev;
> +	unsigned int num_mt_slots;
> +	int id;
> +
> +	num_mt_slots = data->num_touchids + data->num_stylusids;
> +
> +	for (id = 0; id < num_mt_slots; id++) {
> +		input_mt_slot(input_dev, id);
> +		input_mt_report_slot_state(input_dev, MT_TOOL_FINGER, 0);
> +	}
> +
> +	mxt_input_sync(input_dev);
> +}
> +
>  static void mxt_start(struct mxt_data *data)
>  {
> +	if (!data->suspended || data->in_bootloader)
> +		return;
> +
> +	/* Discard any touch messages still in message buffer from before chip
> +	 * went to sleep */
> +	mxt_process_messages_until_invalid(data);
> +
>  	mxt_set_t7_power_cfg(data, MXT_POWER_CFG_RUN);
>  
>  	/* Recalibrate since chip has been in deep sleep */
>  	mxt_t6_command(data, MXT_COMMAND_CALIBRATE, 1, false);
> +
> +	mxt_acquire_irq(data);
> +	data->enable_reporting = true;
> +	data->suspended = false;
>  }
>  
>  static void mxt_stop(struct mxt_data *data)
>  {
> +	if (data->suspended || data->in_bootloader)
> +		return;
> +
> +	data->enable_reporting = false;
> +	disable_irq(data->irq);
> +
>  	mxt_set_t7_power_cfg(data, MXT_POWER_CFG_DEEPSLEEP);
> +
> +	mxt_reset_slots(data);
> +	data->suspended = true;
>  }
>  
>  static int mxt_input_open(struct input_dev *dev)
> -- 
> 1.7.10.4
> 

    Reviewed-by: Henrik Rydberg <rydberg@...omail.se>

Thanks,
Henrik
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/