diff mbox

[v2,2/3] HID: detect Win 8 multitouch devices in core

Message ID 1377099620-23947-3-git-send-email-benjamin.tissoires@redhat.com
State New, archived
Delegated to: Jiri Kosina
Headers show

Commit Message

Benjamin Tissoires Aug. 21, 2013, 3:40 p.m. UTC
Detecting Win 8 multitouch devices in core allows us to set quirks
before the device is parsed through hid_hw_start().
It also simplifies the detection of those devices in hid-multitouch and
makes the handling of those devices cleaner.

As Win 8 multitouch panels are in the group multitouch and rely on a
special feature to be detected, this patch also temporary convert
hid->group into a bitfield, before reverting it to the actual
group information. If we ever have more than 16 groups to detect,
we can then add a .flags field in hid_parser for instance, and then
use this to get the actual group.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
---

changes in v2:
- moved "flags" processing here
- do not introduce parser->flags, but use hid->group as a temporary flag placeholder
- #define and #undef HID_FLAG_* in hid-core.c instead of hid.h
- amended commit message

 drivers/hid/hid-core.c       | 41 +++++++++++++++++++++++++++++++++++++++--
 drivers/hid/hid-multitouch.c | 24 +++++++++++-------------
 include/linux/hid.h          |  1 +
 3 files changed, 51 insertions(+), 15 deletions(-)

Comments

Henrik Rydberg Aug. 21, 2013, 6:26 p.m. UTC | #1
Hi Benjamin,

> Detecting Win 8 multitouch devices in core allows us to set quirks
> before the device is parsed through hid_hw_start().
> It also simplifies the detection of those devices in hid-multitouch and
> makes the handling of those devices cleaner.
> 
> As Win 8 multitouch panels are in the group multitouch and rely on a
> special feature to be detected, this patch also temporary convert
> hid->group into a bitfield, before reverting it to the actual
> group information. If we ever have more than 16 groups to detect,
> we can then add a .flags field in hid_parser for instance, and then
> use this to get the actual group.
> 
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> ---
> 
> changes in v2:
> - moved "flags" processing here
> - do not introduce parser->flags, but use hid->group as a temporary flag placeholder
> - #define and #undef HID_FLAG_* in hid-core.c instead of hid.h
> - amended commit message
> 
>  drivers/hid/hid-core.c       | 41 +++++++++++++++++++++++++++++++++++++++--
>  drivers/hid/hid-multitouch.c | 24 +++++++++++-------------
>  include/linux/hid.h          |  1 +
>  3 files changed, 51 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index e072b15..c749966 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -677,12 +677,25 @@ static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
>  	return NULL;
>  }
>  
> +#define HID_FLAG_MULTITOUCH		(1 << HID_GROUP_MULTITOUCH)
> +#define HID_FLAG_WIN_8_CERTIFIED	(1 << HID_GROUP_MULTITOUCH_WIN_8)
> +#define HID_FLAG_SENSOR_HUB		(1 << HID_GROUP_SENSOR_HUB)
> +

Why not use the existing defines directly? If you worry about being
able to combine bit positions in a simple mask rather than using the
existing bitmask (which could be good), how about a priority list for
the groups instead? My own preference would be to leave structure for
the future to the future, and use a single state in the parser for the
case you are adding.

>  static void hid_scan_input_usage(struct hid_parser *parser, u32 usage)
>  {
>  	struct hid_device *hid = parser->device;
>  
>  	if (usage == HID_DG_CONTACTID)
> -		hid->group = HID_GROUP_MULTITOUCH;
> +		hid->group |= HID_FLAG_MULTITOUCH;
> +}

Dynamic semantics, please no :-) My suggestion: leave this line be...

> +
> +static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage)
> +{
> +	struct hid_device *hid = parser->device;
> +
> +	if (usage == 0xff0000c5 && parser->global.report_count == 256 &&
> +	    parser->global.report_size == 8)
> +		hid->group |= HID_FLAG_WIN_8_CERTIFIED;

And set 'parser->is_win8 = true' here.

>  }
>  
>  static void hid_scan_collection(struct hid_parser *parser, unsigned type)
> @@ -691,7 +704,7 @@ static void hid_scan_collection(struct hid_parser *parser, unsigned type)
>  
>  	if (((parser->global.usage_page << 16) == HID_UP_SENSOR) &&
>  	    type == HID_COLLECTION_PHYSICAL)
> -		hid->group = HID_GROUP_SENSOR_HUB;
> +		hid->group |= HID_FLAG_SENSOR_HUB;

Leave this...

>  }
>  
>  static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
> @@ -714,6 +727,8 @@ static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
>  	case HID_MAIN_ITEM_TAG_OUTPUT:
>  		break;
>  	case HID_MAIN_ITEM_TAG_FEATURE:
> +		for (i = 0; i < parser->local.usage_index; i++)
> +			hid_scan_feature_usage(parser, parser->local.usage[i]);
>  		break;
>  	default:
>  		hid_err(parser->device, "unknown main item tag 0x%x\n",
> @@ -759,10 +774,32 @@ static int hid_scan_report(struct hid_device *hid)
>  	while ((start = fetch_item(start, end, &item)) != NULL)
>  		dispatch_type[item.type](parser, &item);
>  
> +	/*
> +	 * Re-interprete the group field to keep the same group definitions than
> +	 * we had in previous kernels.
> +	 */
> +	switch (hid->group) {
> +	case HID_FLAG_MULTITOUCH:
> +		hid->group = HID_GROUP_MULTITOUCH;
> +		break;
> +	case HID_FLAG_MULTITOUCH | HID_FLAG_WIN_8_CERTIFIED:
> +		hid->group = HID_GROUP_MULTITOUCH_WIN_8;
> +		break;
> +	case HID_FLAG_SENSOR_HUB:
> +		hid->group = HID_GROUP_SENSOR_HUB;
> +		break;
> +	default:
> +		hid->group = HID_GROUP_GENERIC;
> +	}
> +

... and replace this with 'if (parser->is_win8) hid->group = HID_GROUP_MULTITOUCH_WIN_8'.

>  	vfree(parser);
>  	return 0;
>  }
>  
> +#undef HID_FLAG_MULTITOUCH
> +#undef HID_FLAG_WIN_8_CERTIFIED
> +#undef HID_FLAG_SENSOR_HUB
> +

No comment ;-)

>  /**
>   * hid_parse_report - parse device report
>   *
> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> index 0fe00e2..c28ef86 100644
> --- a/drivers/hid/hid-multitouch.c
> +++ b/drivers/hid/hid-multitouch.c
> @@ -133,6 +133,7 @@ static void mt_post_parse(struct mt_device *td);
>  #define MT_CLS_NSMU				0x000a
>  #define MT_CLS_DUAL_CONTACT_NUMBER		0x0010
>  #define MT_CLS_DUAL_CONTACT_ID			0x0011
> +#define MT_CLS_WIN_8				0x0012
>  
>  /* vendor specific classes */
>  #define MT_CLS_3M				0x0101
> @@ -205,6 +206,11 @@ static struct mt_class mt_classes[] = {
>  			MT_QUIRK_CONTACT_CNT_ACCURATE |
>  			MT_QUIRK_SLOT_IS_CONTACTID,
>  		.maxcontacts = 2 },
> +	{ .name = MT_CLS_WIN_8,
> +		.quirks = MT_QUIRK_ALWAYS_VALID |
> +			MT_QUIRK_IGNORE_DUPLICATES |
> +			MT_QUIRK_HOVERING |
> +			MT_QUIRK_CONTACT_CNT_ACCURATE },
>  
>  	/*
>  	 * vendor specific classes
> @@ -332,19 +338,6 @@ static void mt_feature_mapping(struct hid_device *hdev,
>  			td->maxcontacts = td->mtclass.maxcontacts;
>  
>  		break;
> -	case 0xff0000c5:
> -		if (field->report_count == 256 && field->report_size == 8) {
> -			/* Win 8 devices need special quirks */
> -			__s32 *quirks = &td->mtclass.quirks;
> -			*quirks |= MT_QUIRK_ALWAYS_VALID;
> -			*quirks |= MT_QUIRK_IGNORE_DUPLICATES;
> -			*quirks |= MT_QUIRK_HOVERING;
> -			*quirks |= MT_QUIRK_CONTACT_CNT_ACCURATE;
> -			*quirks &= ~MT_QUIRK_NOT_SEEN_MEANS_UP;
> -			*quirks &= ~MT_QUIRK_VALID_IS_INRANGE;
> -			*quirks &= ~MT_QUIRK_VALID_IS_CONFIDENCE;
> -		}
> -		break;
>  	}
>  }
>  
> @@ -1346,6 +1339,11 @@ static const struct hid_device_id mt_devices[] = {
>  
>  	/* Generic MT device */
>  	{ HID_DEVICE(HID_BUS_ANY, HID_GROUP_MULTITOUCH, HID_ANY_ID, HID_ANY_ID) },
> +
> +	/* Generic Win 8 certified MT device */
> +	{  .driver_data = MT_CLS_WIN_8,
> +		HID_DEVICE(HID_BUS_ANY, HID_GROUP_MULTITOUCH_WIN_8,
> +			HID_ANY_ID, HID_ANY_ID) },
>  	{ }
>  };
>  MODULE_DEVICE_TABLE(hid, mt_devices);
> diff --git a/include/linux/hid.h b/include/linux/hid.h
> index 5a4e789..45b7f3f 100644
> --- a/include/linux/hid.h
> +++ b/include/linux/hid.h
> @@ -295,6 +295,7 @@ struct hid_item {
>  #define HID_GROUP_GENERIC			0x0001
>  #define HID_GROUP_MULTITOUCH			0x0002
>  #define HID_GROUP_SENSOR_HUB			0x0003
> +#define HID_GROUP_MULTITOUCH_WIN_8		0x0004
>  
>  /*
>   * This is the global environment of the parser. This information is
> -- 
> 1.8.3.1
> 

Thanks,
Henrik
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Benjamin Tissoires Aug. 22, 2013, 12:01 p.m. UTC | #2
Hi Henrik,

On Wed, Aug 21, 2013 at 8:26 PM, Henrik Rydberg <rydberg@euromail.se> wrote:
> Hi Benjamin,
>
>> Detecting Win 8 multitouch devices in core allows us to set quirks
>> before the device is parsed through hid_hw_start().
>> It also simplifies the detection of those devices in hid-multitouch and
>> makes the handling of those devices cleaner.
>>
>> As Win 8 multitouch panels are in the group multitouch and rely on a
>> special feature to be detected, this patch also temporary convert
>> hid->group into a bitfield, before reverting it to the actual
>> group information. If we ever have more than 16 groups to detect,
>> we can then add a .flags field in hid_parser for instance, and then
>> use this to get the actual group.
>>
>> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
>> ---
>>
>> changes in v2:
>> - moved "flags" processing here
>> - do not introduce parser->flags, but use hid->group as a temporary flag placeholder
>> - #define and #undef HID_FLAG_* in hid-core.c instead of hid.h
>> - amended commit message
>>
>>  drivers/hid/hid-core.c       | 41 +++++++++++++++++++++++++++++++++++++++--
>>  drivers/hid/hid-multitouch.c | 24 +++++++++++-------------
>>  include/linux/hid.h          |  1 +
>>  3 files changed, 51 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
>> index e072b15..c749966 100644
>> --- a/drivers/hid/hid-core.c
>> +++ b/drivers/hid/hid-core.c
>> @@ -677,12 +677,25 @@ static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
>>       return NULL;
>>  }
>>
>> +#define HID_FLAG_MULTITOUCH          (1 << HID_GROUP_MULTITOUCH)
>> +#define HID_FLAG_WIN_8_CERTIFIED     (1 << HID_GROUP_MULTITOUCH_WIN_8)
>> +#define HID_FLAG_SENSOR_HUB          (1 << HID_GROUP_SENSOR_HUB)
>> +
>
> Why not use the existing defines directly? If you worry about being

Just because I need to check both ((1 << HID_GROUP_MULTITOUCH_WIN_8)
&& (1 << HID_GROUP_MULTITOUCH)) which starts being a little bit
difficult to read without the defines.

> able to combine bit positions in a simple mask rather than using the
> existing bitmask (which could be good), how about a priority list for
> the groups instead? My own preference would be to leave structure for
> the future to the future, and use a single state in the parser for the
> case you are adding.

I'd go with a scanning_flags (so a bitmask) in the parser. This will
allows us to add other special case later if required. I don't really
like the idea of having just a boolean is_win8 because IMO the name
should be more explicit, and this will encourage people to add various
flags in the parser.

>
>>  static void hid_scan_input_usage(struct hid_parser *parser, u32 usage)
>>  {
>>       struct hid_device *hid = parser->device;
>>
>>       if (usage == HID_DG_CONTACTID)
>> -             hid->group = HID_GROUP_MULTITOUCH;
>> +             hid->group |= HID_FLAG_MULTITOUCH;
>> +}
>
> Dynamic semantics, please no :-) My suggestion: leave this line be...

ok, will revert it

>
>> +
>> +static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage)
>> +{
>> +     struct hid_device *hid = parser->device;
>> +
>> +     if (usage == 0xff0000c5 && parser->global.report_count == 256 &&
>> +         parser->global.report_size == 8)
>> +             hid->group |= HID_FLAG_WIN_8_CERTIFIED;
>
> And set 'parser->is_win8 = true' here.
>

Again, I'd prefer to go with "parser->scanning_flags |=
HID_SCAN_FLAG_WIN_8_MT_PANEL" (or sth better for the name).

>>  }
>>
>>  static void hid_scan_collection(struct hid_parser *parser, unsigned type)
>> @@ -691,7 +704,7 @@ static void hid_scan_collection(struct hid_parser *parser, unsigned type)
>>
>>       if (((parser->global.usage_page << 16) == HID_UP_SENSOR) &&
>>           type == HID_COLLECTION_PHYSICAL)
>> -             hid->group = HID_GROUP_SENSOR_HUB;
>> +             hid->group |= HID_FLAG_SENSOR_HUB;
>
> Leave this...

ok

>
>>  }
>>
>>  static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
>> @@ -714,6 +727,8 @@ static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
>>       case HID_MAIN_ITEM_TAG_OUTPUT:
>>               break;
>>       case HID_MAIN_ITEM_TAG_FEATURE:
>> +             for (i = 0; i < parser->local.usage_index; i++)
>> +                     hid_scan_feature_usage(parser, parser->local.usage[i]);
>>               break;
>>       default:
>>               hid_err(parser->device, "unknown main item tag 0x%x\n",
>> @@ -759,10 +774,32 @@ static int hid_scan_report(struct hid_device *hid)
>>       while ((start = fetch_item(start, end, &item)) != NULL)
>>               dispatch_type[item.type](parser, &item);
>>
>> +     /*
>> +      * Re-interprete the group field to keep the same group definitions than
>> +      * we had in previous kernels.
>> +      */
>> +     switch (hid->group) {
>> +     case HID_FLAG_MULTITOUCH:
>> +             hid->group = HID_GROUP_MULTITOUCH;
>> +             break;
>> +     case HID_FLAG_MULTITOUCH | HID_FLAG_WIN_8_CERTIFIED:
>> +             hid->group = HID_GROUP_MULTITOUCH_WIN_8;
>> +             break;
>> +     case HID_FLAG_SENSOR_HUB:
>> +             hid->group = HID_GROUP_SENSOR_HUB;
>> +             break;
>> +     default:
>> +             hid->group = HID_GROUP_GENERIC;
>> +     }
>> +
>
> ... and replace this with 'if (parser->is_win8) hid->group = HID_GROUP_MULTITOUCH_WIN_8'.

The test should be:
if ((hid->group == HID_GROUP_MULTITOUCH) && (parser->scanning_flags &
HID_SCAN_FLAG_WIN_8_MT_PANEL))

>
>>       vfree(parser);
>>       return 0;
>>  }
>>
>> +#undef HID_FLAG_MULTITOUCH
>> +#undef HID_FLAG_WIN_8_CERTIFIED
>> +#undef HID_FLAG_SENSOR_HUB
>> +
>
> No comment ;-)

alright. I tried :)

Cheers,
Benjamin

>
>>  /**
>>   * hid_parse_report - parse device report
>>   *
>> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
>> index 0fe00e2..c28ef86 100644
>> --- a/drivers/hid/hid-multitouch.c
>> +++ b/drivers/hid/hid-multitouch.c
>> @@ -133,6 +133,7 @@ static void mt_post_parse(struct mt_device *td);
>>  #define MT_CLS_NSMU                          0x000a
>>  #define MT_CLS_DUAL_CONTACT_NUMBER           0x0010
>>  #define MT_CLS_DUAL_CONTACT_ID                       0x0011
>> +#define MT_CLS_WIN_8                         0x0012
>>
>>  /* vendor specific classes */
>>  #define MT_CLS_3M                            0x0101
>> @@ -205,6 +206,11 @@ static struct mt_class mt_classes[] = {
>>                       MT_QUIRK_CONTACT_CNT_ACCURATE |
>>                       MT_QUIRK_SLOT_IS_CONTACTID,
>>               .maxcontacts = 2 },
>> +     { .name = MT_CLS_WIN_8,
>> +             .quirks = MT_QUIRK_ALWAYS_VALID |
>> +                     MT_QUIRK_IGNORE_DUPLICATES |
>> +                     MT_QUIRK_HOVERING |
>> +                     MT_QUIRK_CONTACT_CNT_ACCURATE },
>>
>>       /*
>>        * vendor specific classes
>> @@ -332,19 +338,6 @@ static void mt_feature_mapping(struct hid_device *hdev,
>>                       td->maxcontacts = td->mtclass.maxcontacts;
>>
>>               break;
>> -     case 0xff0000c5:
>> -             if (field->report_count == 256 && field->report_size == 8) {
>> -                     /* Win 8 devices need special quirks */
>> -                     __s32 *quirks = &td->mtclass.quirks;
>> -                     *quirks |= MT_QUIRK_ALWAYS_VALID;
>> -                     *quirks |= MT_QUIRK_IGNORE_DUPLICATES;
>> -                     *quirks |= MT_QUIRK_HOVERING;
>> -                     *quirks |= MT_QUIRK_CONTACT_CNT_ACCURATE;
>> -                     *quirks &= ~MT_QUIRK_NOT_SEEN_MEANS_UP;
>> -                     *quirks &= ~MT_QUIRK_VALID_IS_INRANGE;
>> -                     *quirks &= ~MT_QUIRK_VALID_IS_CONFIDENCE;
>> -             }
>> -             break;
>>       }
>>  }
>>
>> @@ -1346,6 +1339,11 @@ static const struct hid_device_id mt_devices[] = {
>>
>>       /* Generic MT device */
>>       { HID_DEVICE(HID_BUS_ANY, HID_GROUP_MULTITOUCH, HID_ANY_ID, HID_ANY_ID) },
>> +
>> +     /* Generic Win 8 certified MT device */
>> +     {  .driver_data = MT_CLS_WIN_8,
>> +             HID_DEVICE(HID_BUS_ANY, HID_GROUP_MULTITOUCH_WIN_8,
>> +                     HID_ANY_ID, HID_ANY_ID) },
>>       { }
>>  };
>>  MODULE_DEVICE_TABLE(hid, mt_devices);
>> diff --git a/include/linux/hid.h b/include/linux/hid.h
>> index 5a4e789..45b7f3f 100644
>> --- a/include/linux/hid.h
>> +++ b/include/linux/hid.h
>> @@ -295,6 +295,7 @@ struct hid_item {
>>  #define HID_GROUP_GENERIC                    0x0001
>>  #define HID_GROUP_MULTITOUCH                 0x0002
>>  #define HID_GROUP_SENSOR_HUB                 0x0003
>> +#define HID_GROUP_MULTITOUCH_WIN_8           0x0004
>>
>>  /*
>>   * This is the global environment of the parser. This information is
>> --
>> 1.8.3.1
>>
>
> Thanks,
> Henrik
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diff mbox

Patch

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index e072b15..c749966 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -677,12 +677,25 @@  static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
 	return NULL;
 }
 
+#define HID_FLAG_MULTITOUCH		(1 << HID_GROUP_MULTITOUCH)
+#define HID_FLAG_WIN_8_CERTIFIED	(1 << HID_GROUP_MULTITOUCH_WIN_8)
+#define HID_FLAG_SENSOR_HUB		(1 << HID_GROUP_SENSOR_HUB)
+
 static void hid_scan_input_usage(struct hid_parser *parser, u32 usage)
 {
 	struct hid_device *hid = parser->device;
 
 	if (usage == HID_DG_CONTACTID)
-		hid->group = HID_GROUP_MULTITOUCH;
+		hid->group |= HID_FLAG_MULTITOUCH;
+}
+
+static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage)
+{
+	struct hid_device *hid = parser->device;
+
+	if (usage == 0xff0000c5 && parser->global.report_count == 256 &&
+	    parser->global.report_size == 8)
+		hid->group |= HID_FLAG_WIN_8_CERTIFIED;
 }
 
 static void hid_scan_collection(struct hid_parser *parser, unsigned type)
@@ -691,7 +704,7 @@  static void hid_scan_collection(struct hid_parser *parser, unsigned type)
 
 	if (((parser->global.usage_page << 16) == HID_UP_SENSOR) &&
 	    type == HID_COLLECTION_PHYSICAL)
-		hid->group = HID_GROUP_SENSOR_HUB;
+		hid->group |= HID_FLAG_SENSOR_HUB;
 }
 
 static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
@@ -714,6 +727,8 @@  static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
 	case HID_MAIN_ITEM_TAG_OUTPUT:
 		break;
 	case HID_MAIN_ITEM_TAG_FEATURE:
+		for (i = 0; i < parser->local.usage_index; i++)
+			hid_scan_feature_usage(parser, parser->local.usage[i]);
 		break;
 	default:
 		hid_err(parser->device, "unknown main item tag 0x%x\n",
@@ -759,10 +774,32 @@  static int hid_scan_report(struct hid_device *hid)
 	while ((start = fetch_item(start, end, &item)) != NULL)
 		dispatch_type[item.type](parser, &item);
 
+	/*
+	 * Re-interprete the group field to keep the same group definitions than
+	 * we had in previous kernels.
+	 */
+	switch (hid->group) {
+	case HID_FLAG_MULTITOUCH:
+		hid->group = HID_GROUP_MULTITOUCH;
+		break;
+	case HID_FLAG_MULTITOUCH | HID_FLAG_WIN_8_CERTIFIED:
+		hid->group = HID_GROUP_MULTITOUCH_WIN_8;
+		break;
+	case HID_FLAG_SENSOR_HUB:
+		hid->group = HID_GROUP_SENSOR_HUB;
+		break;
+	default:
+		hid->group = HID_GROUP_GENERIC;
+	}
+
 	vfree(parser);
 	return 0;
 }
 
+#undef HID_FLAG_MULTITOUCH
+#undef HID_FLAG_WIN_8_CERTIFIED
+#undef HID_FLAG_SENSOR_HUB
+
 /**
  * hid_parse_report - parse device report
  *
diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 0fe00e2..c28ef86 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -133,6 +133,7 @@  static void mt_post_parse(struct mt_device *td);
 #define MT_CLS_NSMU				0x000a
 #define MT_CLS_DUAL_CONTACT_NUMBER		0x0010
 #define MT_CLS_DUAL_CONTACT_ID			0x0011
+#define MT_CLS_WIN_8				0x0012
 
 /* vendor specific classes */
 #define MT_CLS_3M				0x0101
@@ -205,6 +206,11 @@  static struct mt_class mt_classes[] = {
 			MT_QUIRK_CONTACT_CNT_ACCURATE |
 			MT_QUIRK_SLOT_IS_CONTACTID,
 		.maxcontacts = 2 },
+	{ .name = MT_CLS_WIN_8,
+		.quirks = MT_QUIRK_ALWAYS_VALID |
+			MT_QUIRK_IGNORE_DUPLICATES |
+			MT_QUIRK_HOVERING |
+			MT_QUIRK_CONTACT_CNT_ACCURATE },
 
 	/*
 	 * vendor specific classes
@@ -332,19 +338,6 @@  static void mt_feature_mapping(struct hid_device *hdev,
 			td->maxcontacts = td->mtclass.maxcontacts;
 
 		break;
-	case 0xff0000c5:
-		if (field->report_count == 256 && field->report_size == 8) {
-			/* Win 8 devices need special quirks */
-			__s32 *quirks = &td->mtclass.quirks;
-			*quirks |= MT_QUIRK_ALWAYS_VALID;
-			*quirks |= MT_QUIRK_IGNORE_DUPLICATES;
-			*quirks |= MT_QUIRK_HOVERING;
-			*quirks |= MT_QUIRK_CONTACT_CNT_ACCURATE;
-			*quirks &= ~MT_QUIRK_NOT_SEEN_MEANS_UP;
-			*quirks &= ~MT_QUIRK_VALID_IS_INRANGE;
-			*quirks &= ~MT_QUIRK_VALID_IS_CONFIDENCE;
-		}
-		break;
 	}
 }
 
@@ -1346,6 +1339,11 @@  static const struct hid_device_id mt_devices[] = {
 
 	/* Generic MT device */
 	{ HID_DEVICE(HID_BUS_ANY, HID_GROUP_MULTITOUCH, HID_ANY_ID, HID_ANY_ID) },
+
+	/* Generic Win 8 certified MT device */
+	{  .driver_data = MT_CLS_WIN_8,
+		HID_DEVICE(HID_BUS_ANY, HID_GROUP_MULTITOUCH_WIN_8,
+			HID_ANY_ID, HID_ANY_ID) },
 	{ }
 };
 MODULE_DEVICE_TABLE(hid, mt_devices);
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 5a4e789..45b7f3f 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -295,6 +295,7 @@  struct hid_item {
 #define HID_GROUP_GENERIC			0x0001
 #define HID_GROUP_MULTITOUCH			0x0002
 #define HID_GROUP_SENSOR_HUB			0x0003
+#define HID_GROUP_MULTITOUCH_WIN_8		0x0004
 
 /*
  * This is the global environment of the parser. This information is