RE: [PATCH 1/2] Input: elan_i2c - Add new trackpoint report type 0x5F.

["jingle" <jingle.wu@emc.com.tw>]

HI Dmitry:

I would prefer if we validated report length versus the packet type before
accepting it.

-> If the tracking point report is 0x5F, the report length is 7, but the
touchpad report length is 32.
-> So, report length will be different with this module.

THANKS
JINGLE


-----Original Message-----
From: Dmitry Torokhov [mailto:dmitry.torokhov@gmail.com] 
Sent: Thursday, December 10, 2020 2:14 PM
To: jingle.wu
Cc: linux-kernel@vger.kernel.org; linux-input@vger.kernel.org;
phoenix@emc.com.tw; josh.chen@emc.com.tw; dave.wang@emc.com.tw
Subject: Re: [PATCH 1/2] Input: elan_i2c - Add new trackpoint report type
0x5F.

Hi Jingle,

On Mon, Dec 07, 2020 at 05:07:51PM +0800, jingle.wu wrote:
> The 0x5F is new trackpoint report type of some module.
> 
> Signed-off-by: Jingle Wu <jingle.wu@emc.com.tw>
> ---
>  drivers/input/mouse/elan_i2c_core.c  | 2 ++  
> drivers/input/mouse/elan_i2c_smbus.c | 3 ++-
>  2 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/mouse/elan_i2c_core.c 
> b/drivers/input/mouse/elan_i2c_core.c
> index 61ed3f5ca219..8f0c4663167c 100644
> --- a/drivers/input/mouse/elan_i2c_core.c
> +++ b/drivers/input/mouse/elan_i2c_core.c
> @@ -52,6 +52,7 @@
>  #define ETP_REPORT_ID		0x5D
>  #define ETP_REPORT_ID2		0x60	/* High precision report */
>  #define ETP_TP_REPORT_ID	0x5E
> +#define ETP_TP_REPORT_ID2	0x5F
>  #define ETP_REPORT_ID_OFFSET	2
>  #define ETP_TOUCH_INFO_OFFSET	3
>  #define ETP_FINGER_DATA_OFFSET	4

I think we might need to move this into elan_i2c.h so that we can reference
it from elan_i2c_smbus.c.

> @@ -1076,6 +1077,7 @@ static irqreturn_t elan_isr(int irq, void *dev_id)
>  		elan_report_absolute(data, report, true);
>  		break;
>  	case ETP_TP_REPORT_ID:
> +	case ETP_TP_REPORT_ID2:
>  		elan_report_trackpoint(data, report);
>  		break;
>  	default:
> diff --git a/drivers/input/mouse/elan_i2c_smbus.c 
> b/drivers/input/mouse/elan_i2c_smbus.c
> index 1820f1cfc1dc..1226d47ec3cf 100644
> --- a/drivers/input/mouse/elan_i2c_smbus.c
> +++ b/drivers/input/mouse/elan_i2c_smbus.c
> @@ -45,6 +45,7 @@
>  #define ETP_SMBUS_CALIBRATE_QUERY	0xC5
>  
>  #define ETP_SMBUS_REPORT_LEN		32
> +#define ETP_SMBUS_REPORT_LEN2		7
>  #define ETP_SMBUS_REPORT_OFFSET		2
>  #define ETP_SMBUS_HELLOPACKET_LEN	5
>  #define ETP_SMBUS_IAP_PASSWORD		0x1234
> @@ -497,7 +498,7 @@ static int elan_smbus_get_report(struct i2c_client
*client,
>  		return len;
>  	}
>  
> -	if (len != ETP_SMBUS_REPORT_LEN) {
> +	if ((len != ETP_SMBUS_REPORT_LEN) && (len != ETP_SMBUS_REPORT_LEN2))

> +{

I would prefer if we validated report length versus the packet type before
accepting it.

>  		dev_err(&client->dev,
>  			"wrong report length (%d vs %d expected)\n",
>  			len, ETP_SMBUS_REPORT_LEN);
> --
> 2.17.1
> 

Thanks.

-- 
Dmitry