Re: [PATCH 1/4] HID: wacom: retrieve name from HID descriptor for generic devices

[Jason Gerecke <killertofu@gmail.com>]

On 4/15/2015 4:52 PM, Ping Cheng wrote:
> HID generic devices share the same default name, "Wacom HID". This
> causes userland programs to show same device names for different
> devices, which would confuse end users with same device names for
> different devices too.
> 
> This patch uses name retrieved from HID descriptor, if a meaningful
> name is reported. Otherwise, affix its product ID to "Wacom HID".
> 
> Signed-off-by: Ping Cheng <pingc@wacom.com>
> ---
>  drivers/hid/wacom_sys.c | 45 ++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 34 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
> index 1b00d8d..4c5d924 100644
> --- a/drivers/hid/wacom_sys.c
> +++ b/drivers/hid/wacom_sys.c
> @@ -1392,6 +1392,39 @@ static size_t wacom_compute_pktlen(struct hid_device *hdev)
>  	return size;
>  }
>  
> +static void wacom_update_name(struct wacom *wacom)
> +{
> +	struct wacom_wac *wacom_wac = &wacom->wacom_wac;
> +	struct wacom_features *features = &wacom_wac->features;
> +
> +	/* Generic devices name unspecified */
> +	if ((features->type == HID_GENERIC) && !strcmp("Wacom HID", features->name)) {
> +		if (strstr(wacom->hdev->name, "Wacom") ||
> +		    strstr(wacom->hdev->name, "wacom") ||
> +		    strstr(wacom->hdev->name, "WACOM")) {
> +			/* name is in HID descriptor, use it */
> +			strlcpy(wacom_wac->name, wacom->hdev->name,
> +				sizeof(wacom_wac->name));
> +		} else {
> +			/* no meaningful name retrieved. use product ID */
> +			snprintf(wacom_wac->name, sizeof(wacom_wac->name),
> +					 "%s %x", features->name, wacom_wac->pid);

'wacom_wac->pid' doesn't seem to have been initialized at this point.
'wacom->hdev->product' works, however.

> +		}
> +	} else {
> +		strlcpy(wacom_wac->name, features->name, sizeof(wacom_wac->name));
> +	}
> +	snprintf(wacom_wac->pad_name, sizeof(wacom_wac->pad_name),
> +		"%s Pad", wacom_wac->name);
> +
> +	/* Append the device type to the name */
> +	if (features->device_type != BTN_TOOL_FINGER)
> +		strlcat(wacom_wac->name, " Pen", WACOM_NAME_MAX);
> +	else if (features->touch_max)
> +		strlcat(wacom_wac->name, " Finger", WACOM_NAME_MAX);
> +	else
> +		strlcat(wacom_wac->name, " Pad", WACOM_NAME_MAX);

Some of the ISDv4 names seem to be full of excess whitespace. For
example, I see names like:

Wacom Co.,Ltd.       Pen and MultiTouch Sensor   Pen
Wacom Co.,Ltd.       Pen and MultiTouch Sensor   Touch

I'd suggest adding an additional block similar to the following at this
point in the code to fix it:

/* strip out excess whitespace */
while (1) {
	char *gap = strstr(wacom-wac->name, "  ");
	if (gap == NULL)
		break;
	memmove(gap, gap+1, strlen(gap+1)+1);
}

-- 
Jason
---
Now instead of four in the eights place /
you’ve got three, ‘Cause you added one /
(That is to say, eight) to the two, /
But you can’t take seven from three, /
So you look at the sixty-fours....

> +}
> +
>  static int wacom_probe(struct hid_device *hdev,
>  		const struct hid_device_id *id)
>  {
> @@ -1517,17 +1550,7 @@ static int wacom_probe(struct hid_device *hdev,
>  	}
>  	wacom_calculate_res(features);
>  
> -	strlcpy(wacom_wac->name, features->name, sizeof(wacom_wac->name));
> -	snprintf(wacom_wac->pad_name, sizeof(wacom_wac->pad_name),
> -		"%s Pad", features->name);
> -
> -	/* Append the device type to the name */
> -	if (features->device_type != BTN_TOOL_FINGER)
> -		strlcat(wacom_wac->name, " Pen", WACOM_NAME_MAX);
> -	else if (features->touch_max)
> -		strlcat(wacom_wac->name, " Finger", WACOM_NAME_MAX);
> -	else
> -		strlcat(wacom_wac->name, " Pad", WACOM_NAME_MAX);
> +	wacom_update_name(wacom);
>  
>  	error = wacom_add_shared_data(hdev);
>  	if (error)
> 

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