From 6deeb4874ad7bd4d1097eae062bdfa265a1e4212 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Bla=C5=BE=20Hrastnik?= Date: Wed, 6 Nov 2019 20:02:46 +0900 Subject: [PATCH] HID: Improve Windows Precision Touchpad detection. MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit [ 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 Signed-off-by: Benjamin Tissoires Signed-off-by: Sasha Levin --- 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 42d1b350afd2..c89eb3c3965c 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -761,6 +761,10 @@ 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