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

From: Benjamin Tissoires
Date: Wed Dec 10 2014 - 15:51:09 EST


On Mon, Dec 8, 2014 at 7:16 PM, Andrew Duggan <aduggan@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx>
>> ---
>> 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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