Re: [PATCH 2/2] HID: logitech-hidpp: prefix the name with Logitech

[Peter Wu <peter@lekensteyn.nl>]

On Wednesday 10 December 2014 17:21:10 Benjamin Tissoires wrote:
> Current names are reported as "K750", "M705", and it can be misleading
> for the users when they look at their input device list.
> 
> Prefixing the names with "Logitech " makes things better.

Doesn't this apply to all input devices? Like, every USB device can be
queried for the manufacturer which could then by included by the input
subsystem.

What about duplicate names? Can this patch cause a conflict with devices
having the same name?

> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> ---
> 
> Hi Jiri,
> 
> I'd love to see this one in 3.19 (after a strong review, of course).
> The idea came with the mouse DPI database that Peter is currently working on
> (see http://who-t.blogspot.com.au/2014/12/building-a-dpi-database-for-mice.html).
> 
> I think, if you do not qualify the series for 3.19, we should drop it entirely.
> 3.19 introduces the hidpp module and changes the labels. The DPI hwdb will check
> on the label to match the actual mouse, so if this one does not get into 3.19,
> we will end up in 3 entries for each Logitech device.
> 
> Cheers,
> Benjamin
> 
> 
>  drivers/hid/hid-logitech-hidpp.c | 34 ++++++++++++++++++++++++++++++++++
>  1 file changed, 34 insertions(+)
> 
> diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
> index 3846305..8cf4352 100644
> --- a/drivers/hid/hid-logitech-hidpp.c
> +++ b/drivers/hid/hid-logitech-hidpp.c
> @@ -282,6 +282,33 @@ static inline bool hidpp_report_is_connect_event(struct hidpp_report *report)
>  		(report->rap.sub_id == 0x41);
>  }
>  
> +/**
> + * hidpp_prefix_name() prefixes the current given name with "Logitech ".
> + */
> +static void hidpp_prefix_name(char **name, int name_length)
> +{
> +#define PREFIX_SIZE 9 /* "Logitech " */
> +
> +	int new_length;
> +	char *new_name;
> +
> +	if (name_length > PREFIX_SIZE &&
> +	    strncmp(*name, "Logitech ", PREFIX_SIZE) == 0)

I think you meant || here, not &&.

> +		/* The prefix has is already in the name */
> +		return;
> +
> +	new_length = name_length + PREFIX_SIZE;

Stylistic note, but 'PREFIX_SIZE + name_length' would match the order of
the string that gets prepended.

Kind regards,
Peter

> +	new_name = kzalloc(new_length, GFP_KERNEL);
> +	if (!new_name)
> +		return;
> +
> +	snprintf(new_name, new_length, "Logitech %s", *name);
> +
> +	kfree(*name);
> +
> +	*name = new_name;
> +}
> +
>  /* -------------------------------------------------------------------------- */
>  /* HIDP++ 1.0 commands                                                        */
>  /* -------------------------------------------------------------------------- */
> @@ -318,6 +345,10 @@ static char *hidpp_get_unifying_name(struct hidpp_device *hidpp_dev)
>  		return NULL;
>  
>  	memcpy(name, &response.rap.params[2], len);
> +
> +	/* include the terminating '\0' */
> +	hidpp_prefix_name(&name, len + 1);
> +
>  	return name;
>  }
>  
> @@ -489,6 +520,9 @@ static char *hidpp_get_device_name(struct hidpp_device *hidpp)
>  			feature_index, index, name + index,
>  			__name_length - index);
>  
> +	/* include the terminating '\0' */
> +	hidpp_prefix_name(&name, __name_length + 1);
> +
>  	return name;
>  
>  out_err:
>