| From 6d7c1c19f6885a20e9bf07635439c37a11e627c9 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Wed, 6 Nov 2019 20:02:46 +0900 |
| Subject: HID: Improve Windows Precision Touchpad detection. |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| From: Blaž Hrastnik <blaz@mxxn.io> |
| |
| [ Upstream commit 2dbc6f113acd74c66b04bf49fb027efd830b1c5a ] |
| |
| Per Microsoft spec, usage 0xC5 (page 0xFF) returns a blob containing |
| data used to verify the touchpad as a Windows Precision Touchpad. |
| |
| 0x85, REPORTID_PTPHQA, // REPORT_ID (PTPHQA) |
| 0x09, 0xC5, // USAGE (Vendor Usage 0xC5) |
| 0x15, 0x00, // LOGICAL_MINIMUM (0) |
| 0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (0xff) |
| 0x75, 0x08, // REPORT_SIZE (8) |
| 0x96, 0x00, 0x01, // REPORT_COUNT (0x100 (256)) |
| 0xb1, 0x02, // FEATURE (Data,Var,Abs) |
| |
| However, some devices, namely Microsoft's Surface line of products |
| instead implement a "segmented device certification report" (usage 0xC6) |
| which returns the same report, but in smaller chunks. |
| |
| 0x06, 0x00, 0xff, // USAGE_PAGE (Vendor Defined) |
| 0x85, REPORTID_PTPHQA, // REPORT_ID (PTPHQA) |
| 0x09, 0xC6, // USAGE (Vendor usage for segment #) |
| 0x25, 0x08, // LOGICAL_MAXIMUM (8) |
| 0x75, 0x08, // REPORT_SIZE (8) |
| 0x95, 0x01, // REPORT_COUNT (1) |
| 0xb1, 0x02, // FEATURE (Data,Var,Abs) |
| 0x09, 0xC7, // USAGE (Vendor Usage) |
| 0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (0xff) |
| 0x95, 0x20, // REPORT_COUNT (32) |
| 0xb1, 0x02, // FEATURE (Data,Var,Abs) |
| |
| By expanding Win8 touchpad detection to also look for the segmented |
| report, all Surface touchpads are now properly recognized by |
| hid-multitouch. |
| |
| Signed-off-by: Blaž Hrastnik <blaz@mxxn.io> |
| Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/hid/hid-core.c | 4 ++++ |
| 1 file changed, 4 insertions(+) |
| |
| diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c |
| index b0c8fae7f903..3a359716fb38 100644 |
| --- a/drivers/hid/hid-core.c |
| +++ b/drivers/hid/hid-core.c |
| @@ -780,6 +780,10 @@ static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage) |
| if (usage == 0xff0000c5 && parser->global.report_count == 256 && |
| parser->global.report_size == 8) |
| parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8; |
| + |
| + if (usage == 0xff0000c6 && parser->global.report_count == 1 && |
| + parser->global.report_size == 8) |
| + parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8; |
| } |
| |
| static void hid_scan_collection(struct hid_parser *parser, unsigned type) |
| -- |
| 2.20.1 |
| |
