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 42d1b350afd2a..c89eb3c3965cb 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)