linux-kernel - Re: [PATCH] HID: rmi: Add support for the touchpad in the Razer Blade 14 laptop

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Date:	Wed, 10 Dec 2014 15:51:01 -0500
From:	Benjamin Tissoires <benjamin.tissoires@...il.com>
To:	Andrew Duggan <aduggan@...aptics.com>
Cc:	linux-input <linux-input@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Jiri Kosina <jkosina@...e.cz>,
	Benjamin Tissoires <benjamin.tissoires@...hat.com>
Subject: Re: [PATCH] HID: rmi: Add support for the touchpad in the Razer Blade
 14 laptop

On Mon, Dec 8, 2014 at 7:16 PM, Andrew Duggan <aduggan@...aptics.com> wrote:
> On 11/24/2014 04:20 PM, Andrew Duggan wrote:
>>
>> The Razer Blade 14 has a Synaptic's TouchPad on one of the interfaces of
>> a composite USB device. This patch allows the hid-rmi driver to bind
>> to that interface. It also adds support for the external click buttons
>> on the Razer's touchpad. External buttons are reported using generic
>> mouse reports instead of through the F30 like it is on ClickPads.
>>
>> Signed-off-by: Andrew Duggan <aduggan@...aptics.com>
>> ---
>> This patch depends on the "HID: rmi: Scan the report descriptor to
>> determine if the device is
>> suitable for the hid-rmi driver" I submitted earlier today to correctly
>> bind to the touchpad HID
>> device in the composite USB device.
>
> Any comments on this patch?

Again, sorry for the lag on this series. I think now that I re-read
this one I understood why I did not put too many efforts to properly
review the series. This one is a little bit worrisome IMO.

>
> Thanks,
> Andrew
>
>>   drivers/hid/hid-core.c |  4 +++-
>>   drivers/hid/hid-ids.h  |  3 +++
>>   drivers/hid/hid-rmi.c  | 15 ++++++++++++++-
>>   3 files changed, 20 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
>> index ba9dc59..d69ea16 100644
>> --- a/drivers/hid/hid-core.c
>> +++ b/drivers/hid/hid-core.c
>> @@ -792,7 +792,9 @@ static int hid_scan_report(struct hid_device *hid)
>>         /*
>>         * Vendor specific handlings
>>         */
>> -       if ((hid->vendor == USB_VENDOR_ID_SYNAPTICS) &&
>> +       if ((hid->vendor == USB_VENDOR_ID_SYNAPTICS
>> +           || (hid->vendor == USB_VENDOR_ID_RAZER
>> +           && hid->product == USB_DEVICE_ID_RAZER_BLADE_14)) &&

I don't like this. We already have a blacklist, an ignore list, and
there, we will have a new blacklist...

I understood why you put this here, the current have_special_driver
list will not fit 100%. Still, I find it not good.

It works, but I think we should still head for an entry in
have_special_driver, and a specific behavior in hid-rmi which would
rely on hid-input to handle the keyboard/mouse buttons and the rest.

>>             (hid->group == HID_GROUP_GENERIC)) {
>>                 if ((parser->scan_flags & HID_SCAN_FLAG_VENDOR_SPECIFIC)
>>                     && (parser->scan_flags &
>> HID_SCAN_FLAG_GENDESK_POINTER))
>> diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
>> index 25cd674..c677aad 100644
>> --- a/drivers/hid/hid-ids.h
>> +++ b/drivers/hid/hid-ids.h
>> @@ -751,6 +751,9 @@
>>   #define USB_DEVICE_ID_QUANTA_OPTICAL_TOUCH_3001               0x3001
>>   #define USB_DEVICE_ID_QUANTA_OPTICAL_TOUCH_3008               0x3008
>>   +#define USB_VENDOR_ID_RAZER          0x1532
>> +#define USB_DEVICE_ID_RAZER_BLADE_14   0x011D
>> +
>>   #define USB_VENDOR_ID_REALTEK         0x0bda
>>   #define USB_DEVICE_ID_REALTEK_READER  0x0152
>>   diff --git a/drivers/hid/hid-rmi.c b/drivers/hid/hid-rmi.c
>> index 3cccff7..1f131df 100644
>> --- a/drivers/hid/hid-rmi.c
>> +++ b/drivers/hid/hid-rmi.c
>> @@ -453,7 +453,15 @@ static int rmi_raw_event(struct hid_device *hdev,
>>         case RMI_ATTN_REPORT_ID:
>>                 return rmi_input_event(hdev, data, size);
>>         case RMI_MOUSE_REPORT_ID:
>> -               rmi_schedule_reset(hdev);
>> +               /*
>> +                * touchpads with physical mouse buttons will report those
>> +                * buttons in mouse reports even in RMI mode. Only reset
>> +                * the device if we see reports which contain X or Y data.
>> +                */
>> +               if (data[2] != 0 || data[3] != 0)

this seems a little bit magical. There may not be an other solution,
but I would prefer that we look at alternatives before using this
magical numbers (will the touchpad always use the same report
descriptor on the mouse interface?)

>> +                       rmi_schedule_reset(hdev);
>> +               else
>> +                       return 1;
>>                 break;
>>         }
>>   @@ -871,6 +879,11 @@ static int rmi_input_mapping(struct hid_device
>> *hdev,
>>                 struct hid_input *hi, struct hid_field *field,
>>                 struct hid_usage *usage, unsigned long **bit, int *max)
>>   {
>> +       if (field->application == HID_GD_POINTER
>> +               && (usage->hid & HID_USAGE_PAGE) == HID_UP_BUTTON)
>> +               /* Pass mouse button reports to generic code for
>> processing */
>> +               return 0;
>> +
>>         /* we want to make HID ignore the advertised HID collection */
>>         return -1;
>>   }
>
>

Cheers,
Benjamin
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